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Guidelines Part 20

Guidelines Part 20 Contents

Guidelines Part 20 - Definitions

G20.1 Construction project-routine maintenance

Issued August 1999

The definition of construction project includes reference to "routine maintenance". Routine maintenance includes activities such as painting or glass replacement that are required as part of owning and operating a building or facility. A NOP is not required unless a particular maintenance project triggers one of the criteria listed in section 20.2 of the OHS Regulation, for example the total cost of a painting project will exceed $100,000.

Guidelines Part 20 - General requirements

G20.2(1)(a) Notice of project

Issued August 1999; Editorial Revision October 2004

Section 20.2(1)(a) of the OHS Regulation states "The owner or, if the owner engages another person to be the prime contractor, then that person must ensure that the board receives, in writing or by fax, a notice of project (NOP) at least 24 hours before starting a construction project if...(a) the total cost of labour and materials for the work exceeds $100,000, or..."

Board prevention officers and managers monitor the notices regarding activity in their area and select projects for follow-up in accordance with their Worksafe objectives, the nature of the project or other circumstances. The Board is not obliged to initiate a site inspection in every case when a NOP is received.

G20.2(1)(f) Bell holes

Issued August 1999

Work around underground pipe and conduits usually involves digging "bell holes" for maintenance such as fixing leaks or breaks, or servicing valves. A bell hole is considered to be a trench, as long as the criteria in the definition for a trench in section 20.1 of the OHS Regulation is met. This means its width at the bottom cannot exceed 3.7 metres (12 feet). If the work related to a bell hole excavation triggers one of the criteria listed in section 20.78(1) requiring a professional engineer's instructions, or invokes one of the criteria listed in section 20.2, an NOP is required.

Guidelines Part 20 - Safe work areas and safe access

G20.4(1) Suitable ladders, work platforms, and scaffolds

Preliminary Issue August 13, 2008

Regulatory excerpt
Section 4.61 of the OHS Regulation ("Regulation") states:

Elevated walkways must be at least 50 cm (20 in) wide, and safe access to walkways must be provided by means of stairs, ramps or fixed ladders.

Section 13.1 of the Regulation states, in part:

"scaffold" means any temporary elevated work platform and its supporting structure used for supporting workers, materials or equipment;

"work platform" means an elevated or suspended temporary work surface used for supporting workers and includes a scaffold and boatswain's chair.

Section 13.6(1) of the Regulation states:

If work cannot be done from a ladder without hazard to a worker, a work platform must be provided.

Section 13.14(1) of the Regulation states:

The platform of each scaffold must
(a) be a minimum nominal width of 50 cm (20 in), except that a nominal 30 cm (12 in) wide work platform may be used with ladder jacks, pump jack or similar systems,
(b) not leave more than one opening in the work platform, which must be no greater than 25 cm (10 in) in width, and
(c) if not level, be designed to ensure adequate footing for workers using the platform.

Section 20.4(1) of the Regulation states:

Where practicable, suitable ladders, work platforms and scaffolds meeting the requirements of Part 13 (Ladders, Scaffold and Temporary Work Platforms) must be provided for and used by a worker for activities requiring positioning at elevations above a floor or grade.

Purpose of guideline
The purpose of this guideline is to discuss suitable ladders, work platforms, and scaffoldings, and to specify that the top plate of interior or exterior walls, the top plate, or top walers used in concrete formwork, or other elevated surfaces narrower than a nominal width of 50 cm (20 in) are not considered suitable work platforms. Similarly, the guideline specifies that such surfaces are not acceptable elevated walkways. The guideline also discusses when a ladder is considered suitable.

Application
Section 20.4(1) of the Regulation requires, where practicable, suitable ladders, work platforms, and scaffolds must be provided to and used by workers when their work activities require positioning at elevations above a floor or grade. This includes heights above and below 3 m (10 ft). Work surfaces at elevations above 3 m, or where a fall from a height of less than 3 m involves a risk of injury greater than the risk of injury from the impact on a flat surface, must also comply with the requirements of section 11.2 of the Regulation to use appropriate fall protection.

Suitable ladders, work platforms, and scaffolding
Whether or not a ladder, work platform, or scaffolding will be considered 'suitable' will depend on the intended use. For example, a ladder may be considered suitable when the intention is to only use it for short term, light duty work. However, if the nature of the use will require the maneuvering of heavy objects, such as guiding concrete pump hoses, a ladder would not be considered suitable, and a work platform or scaffolding should be selected. In selecting suitable scaffolding or work platforms, employers have a number of options. Specifically, scaffoldings using manufactured scaffolding brackets, when installed and used in accordance with the manufacturer's instructions, are considered suitable. Single-pole wood scaffolds may also be suitable when properly installed and used. For more information on suitable work platforms and scaffolding, see the following WorkSafeBC publications: Safe Work Practices for House Construction or Construction Safety Series.

Top plate, top waler, or other surface less than 50 cm (20 in) wide is not a suitable work platform or scaffold
Section 20.4(1) of the Regulation requires, where practicable, suitable ladders, work platforms, and scaffolds must be provided to and used by workers when their work activities require positioning at elevations above a floor or grade. If a top plate or other elevated surface is to be used as a temporary work surface, such surfaces must satisfy the requirements for scaffolding and work platforms under Part 13 of the Regulation. Under section 13.14(1)(a), the work platform of a scaffolding must be a minimum nominal width of 50 cm (20 in). The top plate of interior or exterior walls, the top plate or top waler of concrete formwork, the tops of floor or roof joists, the bottom cord of ceiling trusses, or other elevated surfaces narrower than a nominal width of 50 cm (20 in) do not meet this condition. Accordingly, failing to provide or use suitable alternatives to such surfaces where practicable is a violation of section 20.4 of the Regulation.

Elevated walkways
An elevated walkway includes any surface above a floor or grade used by workers or other persons at the workplace to move between two or more areas. Under section 4.61 of the Regulation, an elevated walkway must be at least 50 cm (20 in) wide. This includes top plates used to move from one section of a wall to another, or top walers or tops of concrete formwork used to move from one section of the formwork to another. For a worker to use any such surfaces as an elevated walkway, the surface must be at least 50 cm (20 in) wide. Providing and/or using the top plate of interior or exterior walls, the top plate or top waler of concrete formwork, the tops of floor or roof joists, the bottom cord of ceiling trusses, or other surface narrower than 50 cm (20 in) as an elevated walkway is a violation of section 4.61 of the Regulation.

Use of ladders only when there is no hazard to the worker
Under section 20.4 of the Regulation, a worker who requires positioning at an elevation above a floor or grade may be provided with and use a ladder when the ladder is considered 'suitable' and the requirements of Part 13 of the Regulation are met. Under section 13.6(1), if work cannot be done from a ladder without hazard to the worker, a work platform must be provided. To avoid exposing a worker to a hazard, work from a ladder should be limited to light duty work where the ladder will be at any one spot for sporadic, short-term work. This may include marking out where floor joists or trusses will be, or other activities where the worker can reasonably maintain three points of contact with the ladder. Work such as aligning floor joists or trusses, guiding concrete pump hoses, or other activities that require the worker to maneuver heavy objects, is not acceptable. These activities are considered to expose the worker to a hazard if conducted from a ladder. A failure to provide or use a work platform where work from a ladder exposes the worker to a hazard is a violation of section 13.6(1) of the Regulation.

G20.4(2) Suitable access for safe delivery of equipment and materials

Issued January 1, 2007

Regulatory excerpt
Section 20.4(2) of the OHS Regulation (" Regulation") states:

There must be suitable access for the safe delivery of equipment and materials to locations in the workplace where they will be used.

Purpose of guideline
This guideline provides examples of "equipment and materials" under section 20.4(2) of the Regulation, discusses coordination among workplace parties, and provides examples of safe delivery, interior access, and material handling practices.

"Equipment and materials" under section 20.4(2)
Examples of equipment and materials delivered to building construction sites include but are not limited to drywall, appliances, cabinets, concrete, powered concrete finishing equipment, and trusses. Examples of equipment and materials delivered to road and municipal services construction sites include but are not limited to pipes, hydrants, valves, manhole sections, and portable powered compactors.

Coordination
Prime contractors, owners, employers, supervisors, sub-contractors, and delivery companies all have responsibilities, and must work together to plan and ensure that suitable access is maintained for safe delivery to locations where equipment and materials will be used. See general duty sections under Part 3 of the Workers Compensation Act.

Recommended planning activities include the following:

Developing company and site policy and safe work practices for delivering materials and equipment
Pre-planning the project to provide sufficient clear access points to the site to allow for the safe delivery of equipment and materials
Coordinating delivery times with delivery companies

Safe delivery practices
The following practices, where applicable, can help ensure that materials and equipment are delivered safely:

Clear ground access for telescoping boom forklifts or boom trucks, ensuring the area is

free of overhead hazards, such as power lines
graded and stabilized to provide a solid compacted soil surface or properly shored concrete slab.

Maintain access routes to allow equipment to safely maneuver.
Allow for several locations where materials can be delivered to a floor area.
Make available access openings large enough to safely accommodate passing materials from the boom truck/forklift into the structure.
Minimize manual handling by using boom trucks, lift trucks, or similar material handling equipment to deliver materials and equipment as close as possible to the location where they will be used. Provide sufficient clear access for the material handling equipment.
Eliminate, where practicable, situations where workers manually handle large or heavy items on stairs.
Note: Section 4.50 of the Regulation specifies the controls that are required to eliminate, if practicable, or minimize the risk of musculoskeletal injuries.
Provide guardrail protection and/or anchor points on the structure at wall openings and balconies to enable workers to use appropriate fall protection when transferring materials from the boom truck/forklift into the structure (see also the requirements for fall protection under Part 11 of the Regulation and guardrails under sections 4.58 and 4.58.1).
Install one or more windows temporarily on the inside of the wall to allow easy removal of the window. If windows are not large enough or accessible for the delivery of materials create a temporary access hatch at suitable locations in walls.

Safe interior access practices
Examples of safe interior access practices include the following:

Distribute materials so that the floor in any area is not loaded beyond the permissible floor loadings
Where appropriate, ensure there is sufficient access through framed walls inside the building; for example, ensure that plumbing and electrical wiring runs do not impede workers from carrying materials, such as wallboard, between wall studs to adjacent rooms
Use guardrails to accommodate the safe movement of materials on stairways (see also the requirements for guards and guardrails under sections 4.58 and 4.58.1)
Install stairs leading down to the basement before the delivery of materials to the basement, or if there is no access to the basement, designate areas on the floor where materials can be lowered
Clear hallways and stairs of debris and equipment that may cause slipping and tripping hazards

Appropriate material handling equipment
Ensure material handling equipment, such as boom trucks, rough terrain cranes, forklifts, and telescoping boom lifts, are suitable for use on the site terrain and have sufficient reach and capacity to handle the equipment and materials to the location where workers can safely handle materials and equipment manually.

Note: Section 4.3 of the Regulation provides that the employer must ensure that each piece of equipment in the workplace is capable of safely performing the functions for which it is used, and is selected, used, and operated in accordance with the manufacturer's instructions, safe work practices, and the requirements of the Regulation.

G20.9 Protection from falling materials

Issued August 1999

Section 20.9(3) of the OHS Regulation states "Protective canopies must be designed and constructed to safely support all loads that may reasonably be expected to be applied to them, but in no case less than 2.4 kPa (50 psf)".

Protective canopies are usually of wood frame design. Part 9 of the BC Building Code includes design tables for roof rafters that are rated for 2.5 kPa. Minimum thickness for subflooring and roof sheathing are also specified. A qualified framer should be familiar with the Part 9 requirements and able to interpret the tables correctly. The Appendix in the Building Code allows for the tabulated values to be extrapolated. For example, in applications where a design loading of 5.0 kPa is more appropriate, the spacing between rafters can be halved to achieve the rating.

A free-spanning canopy may not be required to achieve adequate protection. For example, the roof of a typical mobile office trailer has probably not been designed for 2.5 kPa. Additional protection could be achieved by laying sheets of plywood on the roof. Whether plywood alone is sufficient depends on the evaluated hazard. The impact of an object falling onto the plywood represents a dynamic load, and varies in magnitude with the object's mass and the fall distance. Other factors include the stiffness of the object and of the plywood. A heavy hard object falling from a great height onto a rigid surface will impose a high impact load. The minimum design value of 2.5 kPa may be inadequate if this is the potential exposure. Effective implementation will require the application of good judgment to properly identify the hazards.

G20.13(3.1) Ensuring loads do not exceed capacity of thrust-out platforms

Issued June 14, 2004; Revised May 17, 2006

Regulatory excerpt
Section 20.13 of the OHS Regulation states:

(1) A professional engineer must certify each thrust-out crane landing platform and certify that the building structure can adequately support loads to be imposed by use of the platform.

(2) Thrust-out crane landing platform drawings and certification must be available on site when the platform is in place.

(3) The rated capacity of a thrust-out crane landing platform must be clearly marked on the platform and not be exceeded.
(3.1) Control measures acceptable to the Board must be implemented to ensure all loads placed on a thrust-out crane landing platform

(a) are safely supported, and

(b) can be safely attached to and detached from the rigging.

(4) Thrust-out platform decking and supporting members must be designed to safely support any concentrated loads that may be landed.

(5) Repealed (BC Reg. 420/2004).

Purpose of guideline
This guideline describes the measures WorkSafeBC considers acceptable under section 20.13(3.1), to ensure all loads placed on a thrust-out crane landing platform are safely supported and can be safely attached to and detached from the rigging. If a person wishes to use a control system not described in this guideline, an application would need to be made to WorkSafeBC, and the acceptability of that system affirmed in writing by WorkSafeBC before such a system is implemented.

To ensure safe operations on the platform, consideration must be given to more than individual loads placed on the platform by the crane. Other considerations include loads manually placed on the platform, multiple loads, load distribution and stability, as well as safe access for workers connecting and detaching the rigging from the load. The control measures outlined in this guideline involve work procedures or work procedures combined with engineering controls.

A system of nine control measures acceptable to WorkSafeBC is outlined below. The effective implementation of the system requires the fulfillment of the responsibilities by the prime contractor and the employer. The guideline provides three options for determining the weights of loads, and discusses two types of engineering controls that may be used as part of the system to ensure that platforms are not overloaded.

Responsibilities of the prime contractor and employers
The prime contractor, consistent with their responsibilities under section 118 of the Workers Compensation Act ("Act"), is responsible for ensuring that a control system, including appropriate supervision, is in place to prevent thrust-out platforms from being overloaded. That responsibility involves doing everything that is reasonably practicable to establish and maintain the system to ensure worker safety, and to ensure that the activities of employers, workers and other persons at the workplace are coordinated. It is reasonably practicable for the prime contractor to ensure that a control system for thrust-out platforms as described in this guideline is established and maintained.

The employer who arranges for the thrust-out platform to be brought on-site and used must also ensure the safe use of the platform, consistent with their responsibilities under section 115(1) of the Act to protect their workers and any other workers present at the workplace where that employer's work is being carried out. This is typically the formwork contractor.

If another employer wishes to use the thrust-out platform, or if the formwork contractor leaves the site, the ongoing responsibilities of the prime contractor are the key to worker safety, both to ensure the activities of new employers are properly coordinated and that the necessary steps are taken to ensure the safe use of the platform.

Control system
The system for controlling the risks when using thrust-out crane landing platforms includes assigning responsibilities to affected workers, ensuring the rated capacities of platforms are marked and known, ensuring the weights of all loads to be placed on the platform are known, ensuring the platform size is compatible with the loads to be placed on the platform, and a system of supervision is in place. The control system will include the following:

Responsibilities of crane operator: The crane operator has responsibilities that include ensuring that the weight of any load to be landed on the thrust-out platform does not exceed the platform capacity.
Responsibilities of riggers: Riggers are responsible for determining weights of loads to be lifted and communicating the weights to the crane operator, as provided under options A, B or C below. Riggers are to be designated by a responsible authority on-site, and should be qualified to perform their duties by reason of training, education, experience or a combination. Riggers are responsible for ensuring only loads that can be safely attached or detached from the rigging are placed on the platform.
Ensuring rated capacities of platforms are known: Each thrust-out landing platform must be clearly marked with its rated capacity in accordance with section 20.13(3) of the OHS Regulation. The rated capacities of the thrust-out landing platforms are to be made known to the crane operator, to the rigger, and to any other affected person, such as the worker who is monitoring the accumulated loads on thrust-out platforms. An effective means should be in place to ensure these persons can access the information on the rated capacity without delay.
Ensuring an effective means for determining the weights of loads to be lifted by a crane: There are three acceptable options in this guideline for determining the weights of loads: A) an administrative option in which a list of expected weights of loads is used, B) a load cell on the crane, and C) use of a load weighing device on-site. These options are explained in more detail at the end of this list of control measures.
Ensuring an effective means for determining the weights of loads to be placed manually on the platform: The weights of materials or equipment manually placed on the platform will be determined before they are placed. The weights may be determined by calculation, by reference to appropriate documents, or by weighing the load.
Monitoring the total load placed on the platform: A person will be responsible to ensure cumulative loads placed on the platform do not exceed the rated capacity and that the loads are evenly distributed.
Ensuring there is adequate space on the platform: The platform area must be sufficient to allow all loads to be placed such that they will be stable. Generally this will require the loads to fit within the periphery of the platform. Riggers must have sufficient room to access rigging points on the load.
Ensuring an effective system of supervision in place: Supervision is to be provided to ensure the required work procedures are followed.
Ensuring the procedures are made known to all affected workers: This can be done by posting the written procedures on a bulletin board and advising affected workers of them, or by other effective means. Posted procedures need to be kept in legible condition.

Options for determining the weights of loads under element #4 of the control system

A. Administrative option: For this option to be acceptable to WorkSafeBC all the following measures will be in place:

A list of the weights of items to be placed on the platform will be available.
The list will include all the equipment, materials, and other items expected to be placed and will provide the weights for each.
If a garbage box is to be used, the all-up weight of the garbage box will be included in the list. The all-up weight for a garbage box is its dead weight (that is, weight when empty) combined with its rated capacity. For example, if the dead weight of a garbage box is 600 lbs. and the garbage box is rated for 4,000 lbs, the list must show the all-up weight for the box, which is 4,600 lbs;
The list is to be provided to the crane operator, to the rigger, and to any other necessary person, and posted at each platform.
The rigger is responsible for ensuring the bundled loads are in accordance with the supplied list (number of pieces, size, length, etc.). In the case of loads manually placed on the platform, the person placing the load on the platform is responsible for ensuring bundled loads are in accordance with the supplied list.
If an item to be lifted is not on the list, the weight must be determined before it is placed on the platform. In the case of lifted loads, the rigger is responsible to determine the weight of the item and to communicate the weight to the crane operator. If there are repeat lifts of such an item, the list will be updated to include it. If the rigger does not know the weight of a load or cannot with substantial certainty estimate it, then the load is not to be lifted.

B.Load cell on the crane: Under this option, the employer responsible for the crane is to ensure there is an electronic load cell that registers the weight of each load being lifted and displays it to the operator at the controls. Administratively, this is the least complex system, as the crane operator will know the weights directly. There is no need for the rigger to advise the operator of weight information, except when an operator requests an advance estimate before the lift.

C.Load weighing device on-site: This option involves the use of a weighing device separate from the crane. The device is to be used whenever the rigger and crane operator do not have advance information on the weight of a load to be lifted. If the weight displayed by the device cannot be directly observed by the crane operator, it is the responsibility of the rigger to ensure that the weight is communicated to the crane operator.

Engineering controls for limiting the load placed on a platform by a crane
Either of the following two engineering controls may be used to help ensure that a single load placed by a crane does not exceed the rated capacity of a thrust-out platform:

Use of a crane for which the rated capacity at the radius for placing loads on the thrust-out platform does not exceed the rated capacity of the platform.
Adjustment of overload limit switches to effectively reduce the lifting capability of the crane so that it does not exceed the rated capacity of the thrust-out platform.

If such controls are used, the overall control system must still ensure that the platform is not overloaded in circumstances such as multiple loads placed by a crane on the platform, and manual placement of loads on it. In addition, the platform must have adequate space for loads.

Guidelines Part 20 - Concrete formwork and falsework

G20.26 Inspections

Issued August 1999; Editorial Revision April 9, 2008

Regulatory excerpt
Section 20.26(1) of the OHS Regulation ("Regulation") states in part:

Immediately before placement of concrete or other intended loading, the employer must ensure that the concrete formwork and falsework is inspected and an engineering certificate is issued by a professional engineer

Purpose of guideline
This guideline discusses:

What is meant by the phrase "other intended loading"
Acceptable means of conducting inspections and issuing a certificate
What is meant by the phrase "immediately before"

What is meant by "other intended loading"?
When considering this issue, there is a need to keep a broad perspective on the application of sections 20.17 to 20.26 of the Regulation. The broad perspective is falsework is often used to support loads temporarily during construction which are completely unrelated to any concrete formwork. These sections of the Regulation refer to concrete formwork and falsework.

Formwork is defined in section 20.1 as "includes the foundation, supporting structure and mould into which concrete will be placed." Falsework is not defined in the Regulation. Falsework is defined in CSA Standard S269.1, Falsework for Construction Purposes as meaning structural supports and the necessary bracing required for the support of temporary loads during construction. Falsework is defined in the Gage Canadian Dictionary as "a temporary structure that supports a bridge, etc. until the main structure is completed." Neither of these definitions specifically link falsework to concrete work. However, most suspended slab formwork uses falsework as part of the "supporting structure" for the formwork.

Falsework is often used during the erection of steel structures and bridges to temporarily support members until such time as the structural elements can be connected together and braced to be self-supporting and provide a complete structural system. The use of the phrasing "or other intended loading" in section 20.26(1) is to cover the use of such falsework during the erection phase of structures. Falsework may also be required and used during the dismantling or demolition of a structure.

Some parts of sections 20.17 to 20.26 of the Regulation include references to both formwork and falsework. These parts can and should be applied to a falsework system that is not part of formwork. However, some provisions in these sections only reference formwork, and clearly are only applicable to formwork.

The employer has responsibility under sections 4.2, 20.6(2), 20.14, 20.15 and 20.23 (2), (3), and (4) to ensure that any structures or equipment which are being erected, used or dismantled are properly managed to ensure the stability of the structure and that no overloading of any elements takes place. It is under these sections of the Regulation that loads such as bundles of reinforcing steel or sheeting material have to be managed. Based on a recommendation of the Construction Safety Subcommittee during the regulation review process, a reference to bundles of reinforcing steel was included in subsection 20.23(3), to draw attention to the need to manage such loading. Such loads are not intended to be within the scope of "or other intended loading," in section 20.26(1). Hence no inspection and engineering certification under section 20.26(1) should be required prior to their placement.

Clearly section 20.26(1) requires an inspection immediately before placement of concrete. The phrase "other intended loading" in this subsection requires inspection and certification prior to placing the "main" or design load on a falsework that is not part of a formwork. As described above, this would generally be loads such as trusses, beams and similar elements which require temporary support until they can be tied in and secured to perform as an effective structural system, and be self-supporting.

Inspections and certificates
The professional engineer who signs, seals, and issues the written certificate prior to each concrete placing, or application of other intended loading, need not personally inspect the formwork. The engineer must ensure an inspection is done, by the engineer or another qualified person acceptable to the engineer for this purpose, immediately prior to concrete placing, and before the engineer issues the certificate.

What is meant by "immediately before"
The phrase "immediately before" generally means the inspection be done not more than 24 hours prior to the start of concrete placing, and after construction of the formwork for the particular concrete pour has been substantially completed. Inclement weather subsequent to the inspection, or other causes for delay of the concrete placing, will normally necessitate an additional inspection and an engineer to revalidate the inspection certificate.

Guidelines Part 20 - Concrete pumping

G20.40 Use of outriggers on concrete pumping equipment

Issued August 1999, Editorial Revision August 2004; Editorial Revision January 1, 2007; Revised August 31, 2007

Regulatory excerpt
Section 20.40(1) of the OHS Regulation ("Regulation") states:

Outriggers must be used in accordance with the concrete placing boom or mast manufacturer's specifications.

Section 4.3(1) of the Regulation states:

(1) The employer must ensure that each tool, machine and piece of equipment in the workplace is

(a) capable of safely performing the functions for which it is used, and

(b) selected, used and operated in accordance with

(i) the manufacturer's instructions, if available,

(ii) safe work practices, and

(iii) the requirements of this Regulation.

Purpose of guideline
The purpose of this guideline is to set out some guiding principles for determining the "safe work practices" to be followed for deploying outriggers under section 4.3(1)(b)(ii) in circumstances where manufacturer's instructions are either

Not available
If available, the instructions do not address the means of deployment the equipment operator wishes to use in a situation where full deployment of all outriggers is not practicable

This guideline does not address a situation where the operator wishes to deploy outriggers in a manner contrary to the manufacturer's instructions. In that case, the concrete placing firm can contact the manufacturer to ask for a written confirmation of an altered procedure acceptable to the manufacturer. If that is not feasible, for example because the manufacturer is no longer in business, the firm could apply to WorkSafeBC for a variance.

Guiding principles for determining safe work practices
It may be impracticable to fully deploy all outriggers where, for example

The outriggers would put the machine within an unsafe distance to hazards such as excavations and power lines
The outriggers would extend into traffic and the circumstances of the job render it impracticable to get permission to close traffic lanes (closing traffic lanes is generally subject to municipal approval)
An adjacent structure or an excavated or natural bank restricts deployment

It is not considered impracticable to fully deploy all outriggers if the purpose is just to

Increase convenience or save money
Avoid repositioning the pump
Avoid moving stored materials that might reasonably be moved

If the manufacturer's instructions are not available, or do not address the means of deployment where full deployment is not practicable, the following are guiding principles for determining the "safe work practices" under section 4.3(1)(b)(ii) of the Regulation:

1. As far as possible, the worksite should be organized so that concrete pumping equipment can be used with all outriggers fully deployed when the boom or mast is raised. Section 118 of the Workers Compensation Act establishes certain responsibilities on prime contractors at construction projects for complying with the Regulation.

Where this section applies, the prime contractor and the employer of the concrete pump operator share responsibility for selecting the appropriate pump to do the job and for planning the pump's location. If a smaller pump can do the job set-up with all outriggers fully deployed, then it should be used instead of a larger pump that cannot be set up with all outriggers fully deployed. Pump location and setup should be addressed if a pre-job meeting is held.

2. The pump operator should be trained to recognize the circumstances that justify not fully deploying the outriggers.

3. For circumstances where it is impracticable to fully deploy all outriggers, written instructions that address the following factors should be immediately available to the operator.

Safe operating range: This refers to the regions where the boom may be positioned to maintain truck stability. Typically the safe operating range is the area bounded by the lines extending from the centre of rotation of the boom through the centerline of the jacks of the fully deployed outriggers. The boom must never be unfolded or extended outside of the safe operating range.
Outrigger deployment on the pumping side: Typically outriggers must be fully deployed on the side of the equipment over which the boom is extended.
Outrigger deployment on the side opposite to the pumping side: Typically, when it is not practicable to fully deploy all outriggers, the outriggers opposite to the pumping side outriggers must be fully retracted and all jacks lowered to the ground to level the equipment. Structural damage or failure may occur to partially extended telescopic outriggers with the jacks lowered.
Outrigger bearing load: Proper cribbing to distribute the load may be needed if the soil conditions require it.
Procedure for unfolding the boom: Typically the boom will be raised from the cradle, rotated to a position within the safe operating range and then unfolded. If the boom cannot be unfolded within the safe operating range, the other outriggers may have to be fully deployed while the boom is unfolded or folded.
Precautions for over-centre booms (i.e. moving the centre of gravity toward the side that does not have fully extended outriggers): There is potential for backward stability with over-centre booms.

G20.47 Inspection and certification of concrete placing booms and masts

Issued April 4, 2007

Regulatory excerpt
Section 20.47 of the OHS Regulation ("Regulation") states:

A concrete placing boom and mast must be inspected in accordance with good engineering practice at intervals not exceeding 12 months, repaired as necessary, and certified safe for use by a professional engineer, the manufacturer or the manufacturer's authorized agent.

Purpose of guideline
The purpose of this guideline is to outline some of the factors that should be considered when determining if an inspection has been conducted in accordance with "good engineering practice" under this section. It also provides information on who is authorized to certify that

The inspection has been done
A concrete placing boom and mast is safe for use

The concept of good engineering practice
The annual inspection and certification of a concrete placing boom and mast is required by the Regulation. This inspection and certification is to be done in accordance with good engineering practice. The concept of good engineering practice as it applies to this section means inspection, assessment, repair (if necessary), and certification of the equipment, is to be done in consideration of

Applicable regulations, safety codes, and standards
Manufacturer's instructions for operation, inspection, maintenance, servicing, and repair
Operating, maintenance, and service records

Who may do the certification
Certification will generally be done by a professional engineer. If the inspection, assessment, and any necessary repair work is done in B.C., the engineer, as required by the Engineers and Geoscientists Act, must be licensed to practice in B.C. If this work is being done outside B.C., for example in Alberta, the engineer must be licensed to practice in that jurisdiction.

If the certifying agent is a manufacturer's representative, the person signing the certification should be specifically authorized in writing by the manufacturer to make such a certification on behalf of the manufacturer.

For convenience, the professional engineer or equipment manufacturer's representative will be referred to as the "certifying professional" in the remainder of this guideline.

The inspection and certification process
The employer or owner of the equipment should consult the certifying professional in advance to arrange the location of the inspection, testing, and necessary repair work, and to ensure qualified people and adequate facilities are used. Generally the "hands on" part of the inspection, testing, and repair will be done by mechanics, service technicians, non-destructive testing (NDT) technicians, and other qualified workers as necessary (for example, welders), working under the direction of the certifying professional.

Inspection and certification requires assessment of the "critical components," meaning the structural, mechanical, and control system components which affect the safe operation of the equipment. The specific identity of these components will vary from one type of equipment to another, depending on the design and configuration of the equipment.

The frequency of inspections of individual components and the extent of the inspection, including dismantling, assessment and NDT or other testing, will be determined by the certifying professional. The factors relevant in making these determinations include the following:

Requirements of the applicable regulations, safety codes, and standards
The equipment manufacturer's specifications and instructions
The certifying professional's familiarity with the particular design and model of equipment, including known reliability problems or component problems
Previous inspection history and results
Age of the equipment and number of hours of use
Circumstances of use of the equipment (for example, heavy duty vs. light use) and any known incidents since the last certification
The general condition of the equipment
The available use, service, inspection, and maintenance records
The certifying professional's knowledge of the overall effectiveness of the service and maintenance program

Based on the outcomes of the inspection, the certifying professional will determine any necessary repair work.

The certification document will include a statement that the equipment is "safe for use" at the completion of the inspection and any necessary repair work. This means that the equipment should then reasonably be expected to perform safely until the next inspection and certification is required if operated according to the manufacturer's instructions.

If the certifying professional deems it necessary to provide a restricted certification statement (for example, that some components are currently acceptable for safe use but will likely require replacement or renewal before the next annual inspection), the certifying professional will ensure the owner or employer is made aware of these concerns and will also note the condition on the equipment inspection and maintenance records. It is not acceptable for the certifying professional to provide a certification when there are outstanding deficiencies affecting the safe performance or compliance of the equipment with the Regulation.

Guidelines Part 20 - Open web joists and trusses

G20.72 Erection instructions

Issued August 1999

Section 20.72 of the OHS Regulation states

"(1) Work must not be undertaken on the erection of premanufactured open web joists and trusses until clear and appropriate written instructions from a professional engineer or the manufacturer of the joists or trusses, detailing safe erection procedures, are available at the worksite.

(2) Erection and temporary bracing of open web joists and trusses must be done in accordance with the written instructions required by subsection (1)."

The erection of open wood joists and trusses is often performed without adequate (or any) written instructions. The erector receives with the shipment of trusses a set of fabrication sketches that are appropriate for submission to the building inspector. Typically, these sketches indicate permanent bracing requirements, but do not address any procedure or need for temporary bracing.

Existing industry pamphlets produced by trade associations do not always provide adequate detail for the variety of truss configurations that are encountered today. However, several publications by trade associations are applicable and erectors are encouraged to study and employ the applicable procedures recommended in them. The following reference materials may be helpful.

Western Wood Truss Association instructional poster WWTA-EB90 (each member of the Association provides a copy to each site with each truss shipment.)
The Truss Plate Institute publications:
- HIB-91 Summary Sheet,
- HIB-91 Handbook titled "Commentary and Recommendations for Handling, Installing Commentary and Recommendations for Handling, Installing & Bracing Metal Plate Connected Wood Trusses Bracing Metal Plate Connected Wood Trusses", and
- DSB-89 Manual titled " Temporary Bracing of Metal Plate Connected Wood Trusses".
The Canadian Wood Council publishes the following references:
- Wood Design Manual 1995, and
- Introduction to Wood Building Technology (1997).

Work on truss erection should not continue if:

(a) erection and bracing instructions are not available at the site or are obviously incomplete,

(b) work is not being done in accordance with the erection and bracing instructions,

(d) damaged trusses (those with damage such as twisted webs, bent connector plates, cracked chords) are being or have been installed, or

(e) heavy loads are being applied to trusses before all bracing, bridging and decking has been installed.

Guidelines Part 20 - Roof work

G20.75 Fall protection

Issued August 1999; Revised January 1, 2005

Sections 11.2(2) to 11.2(5) of the OHS Regulation state:

(2) The employer must ensure that guardrails meeting the requirements of Part 4 (General Conditions) or other similar means of fall restraint are used when practicable.

(3) If subsection (2) is not practicable, the employer must ensure that another fall restraint system is used.

(4) If subsection (3) is not practicable, the employer must ensure that a fall arrest system is used.

(5) If the use of a fall arrest system is not practicable, or will result in a hazard greater than if the system was not used, the employer must ensure that work procedures are followed that are acceptable to the Board and minimize the risk of injury to a worker from a fall.

Sections 20.75 of the OHS Regulation states:

If a worker is employed on a roof having a slope ratio of 8 vertical to 12 horizontal or greater, the worker must use a personal fall protection system or personnel safety nets must be used, and 38 mm x 140 mm (2 in x 6 in nominal) toe-holds must be used if the roofing material allows for it.

This guideline describes different fall protection systems for work on roofs, according to the amount of slope, using the hierarchy in section 11.2 of the OHS Regulation. Sections 20.74 to 20.77 also need to be considered for roof work.

The general effect of sections 20.74 to 20.77 and Part 11 of the OHS Regulation is to create 3 categories of roofs as illustrated in FIGURE 1 and to provide for different fall protection systems available to be used for each category.

FIGURE 1: 3 CATEGORIES OF ROOFS

Figure 1: 3 Categories of Roofs

1. Fall protection available for flat roofs and roofs up to and including 4 vertical to 12 horizontal:

guardrails,
personal fall protection systems,
safety nets,
control zone,
safety monitor system with control zone, or,
other acceptable work procedures.

2. Fall protection available for roofs with a slope ratio greater than 4 vertical to 12 horizontal but less than 8 vertical to 12 horizontal:

guardrails,
personal fall protection systems,
safety nets, or
other acceptable work procedures.

The control zone and safety monitor systems are not to be employed on roofs steeper than 4 vertical to 12 horizontal. See OHS Guideline G11.2(5)-1.

3. Fall protection available for roofs where the slope ratio is 8 vertical to 12 horizontal or greater

if the roofing material allows for the nailing of toeboards, they must be used, in conjunction with personal fall protection systems or personnel safety nets, as required by section 20.75 of the OHS Regulation, and
if the roofing material preclude the use of toeboards, such as on steel cladding or concrete tile, workers should use roof ladders or acceptable work platforms in conjunction with a personal fall protection system.

Reference should be made to the particular sections of the OHS Regulation governing the methods of fall protection listed above to determine when exactly they can be used and under what conditions. See also OHS Guideline G11.2(5)-1.

G20.77 Mechanical equipment

Issued August 1999, Editorial Revision August 2004

Section 20.77 of the OHS Regulation states:
Mechanical or powered equipment which has the potential to push or pull a worker over an unguarded edge must not be used unless operated according to procedures acceptable to the Board.

Also, section 4.3 of the OHS Regulation requires that equipment must be used and maintained in accordance with the manufacturer's requirements.

Section 20.77 is not intended to apply to small hand tools such as electric drills. It does apply to larger pieces of equipment such as power sweepers.

The equipment should not be used closer than 2 metres (6.5 feet) to the unguarded edge where a safety monitor or other type of work procedure is being used as a fall protection system. The manufacturers of roofing equipment covered by this section typically specify a limit of about this amount in their instructions. If the instructions specify a limit greater than 2 metres, section 20.77 requires that limit be maintained.

Guidelines Part 20 - Excavations

G20.78(1) Vibration, hydrostatic pressure and hazardous ground movement

Issued August 1999; Editorial Revision June 6, 2007

Regulatory Excerpt

Section 20.78(1) of the OHS Regulation states:

Excavation work must be in accordance with the written instructions of a professional engineer if

(a) the excavation is more than 6 m (20 ft) deep,

(b) support structures other than as specified in section 20.81 are used in the excavation,

(c) an improvement or structure is adjacent to the excavation,

(d) the excavation is subject to vibration or hydrostatic pressure likely to result in ground movement hazardous to workers, or

(e) the ground slopes away from the edge of the excavation at an angle steeper than 3 horizontal to 1 vertical.

Purpose of Guideline
The purpose of this guideline is to provide some explanation of the terms "subject to vibration" and "hydrostatic pressure likely to result in ground movement."

Explanation of "subject to vibration"
An excavation may be considered "subject to vibration" under section 20.78(1)(d) if there is activity such as heavy vehicle traffic, blasting, road compaction equipment, or compaction during backfill placement close to the excavation. The severity of the vibrations as well as the distance between the activity to the excavation must be considered.

Hydrostatic pressure and hazardous ground movement
Hydrostatic pressure is a concern if water is coming out of the sides or base of an excavation. Engineering is required unless an effective dewatering system can be implemented. If water can be prevented by the use of a dewatering system, hydrostatic pressure should not be a problem. Using a water pump to remove nominal surface runoff (such as from rainfall) should be acceptable without engineering. If the soil adjacent to an excavation has undergone significant changes in moisture content, the stability of the excavation sides may be in question. Soil that is frozen, or may freeze due to the ambient air temperature during the excavation work, may cause development of hydrostatic pressure and thus such excavation work should only be undertaken following an engineer's instructions.

G20.78(1)(e) Ground slope adjacent to excavation work

Issued February 22, 2005

Section 20.78(1) of the OHS Regulation states:

Excavation work must be in accordance with the written instructions of a professional engineer if

(a) the excavation is more than 6 m (20 ft) deep,

(b) support structures other than as specified in section 20.81 are used in the excavation,

(c) an improvement or structure is adjacent to the excavation,

(d) the excavation is subject to vibration or hydrostatic pressure likely to result in ground movement hazardous to workers, or

(e) the ground slopes away from the edge of the excavation at an angle steeper than 3 horizontal to 1 vertical.

Purpose of guideline
The requirements under section 20.78 address certain circumstances where the general sloping and shoring requirements under section 20.81 do not provide adequate protection for the safety of workers. In these special circumstances, a professional engineer is required to oversee assessment of the site and provide written instructions about performance of the work.

This guideline discusses the circumstance set out in 20.78(1)(e) – as it applies to construction or maintenance work performed along an established road or other similar right of way.

Purpose of 20.78(1)(e)
The intent of section 20.78(1)(e) is to address the hazards arising from situations where the ground slopes up or down from the top edge of an excavation. Where the ground slopes up, the concern is for the increase in lateral ground pressure that arises due to the weight of soil positioned above a 3 horizontal to 1 vertical slope. This weight is an extra load that has not been allowed for in the sloping and shoring requirements specified in section 20.81 of the OHS Regulation. Where the ground slopes down and away, the concern is the lack of adequate lateral support on the downhill side for any bracing specified in section 20.81 positioned against the downhill excavation face.

The control of surface runoff and soil erosion may also be a concern. These concerns arise particularly when the excavation work will be a side hill cut, bulk excavation, or a trench other than in a direction in line with the natural ground slope. Stated another way, if the excavation will generally be "across" the slope in a manner that will change the cross section profile of the slope, section 20.78(1)(e) will apply.

The slopes along a right of way will generally have been designed to provide stable faces to the extent necessary to balance safe and economical functioning of the right of way. Where the right of way was not so designed, but has been in place for at least a year (one full season cycle of rain and/or freezing weather as applicable for the geographical area), the slopes should have reached a natural, stable state. Any excavation activity that will alter the design profile, or naturally stable profile, of a cross section of a slope is within the scope of section 20.78(1)(e).

Excavation work that does not change the cross section of the slope
Some maintenance or construction activities along a right of way may involve minor or localized excavation work that will not alter the "general" cross section profile of a slope in a manner that would affect the overall stability of the slope. Some examples of excavation activity of this type are:

the installation of a utility pole, lamp standard or signpost through use of an auger, drill or similar device to dig a "post hole" or use of a back hoe or other equipment to dig a "bell hole";
cleaning out a drainage ditch or clearing a buffer zone to restore the original design profile and grade;
installing or repairing a shallow culvert running generally in line with the natural ground slope (or perpendicular to the centre line of the right of way);
shouldering work, profiling a road surface, or similar minor excavation work within a compacted roadway; and
a "bell hole" excavated to repair a buried pipe or similar service.

These excavations generally do not require any additional or special sloping or shoring considerations as the dimensions of the excavation are generally small enough that the natural "bridging action" of the soil provides enough support. Also, in most of these cases a worker does not enter into the actual excavation. These type of excavation activities generally do not require any written instructions from a professional engineer.

It must be remembered however, that the hazard of loose material (such as rocks, logs or trees) coming down from a slope above always needs to be evaluated and considered whenever work is being done near the base of the slope. Also, hazards may develop from weather conditions, such as extreme rainfall, or the potential for an avalanche. A "tailboard" or "tool box" meeting should be held with the crew to discuss the conditions in the planned work area prior to starting work. Loose material and weather condition hazards need to be assessed by a qualified person at least daily and preferably, before each work shift. The condition of the slope above must be examined and any loose material that could be a hazard should be removed or stabilized before work starts. If the daily assessment raises any concern regarding the overall stability of the slope, a professional engineer’s assessment and advice should be obtained.

Excavation work that will change the cross section of the slope
There are some excavation activities related to servicing and maintaining a right of way that involve work at or near the base of an unstable or potentially unstable slope and will alter the overall cross section of the slope. Two examples of such activity are slope stabilization and the removal of rock or mud slide material. Prior to starting such work, a professional engineer should oversee the assessment of the conditions in the area to determine if there is a significant risk of substantial material flows (either immediately or as the work proceeds) that could endanger workers.

If the engineer determines there is a significant risk, written instructions on how to proceed (covering aspects such as the sequence of work, selection of equipment, and work methods) need to be obtained from the engineer.

If the engineer determines there is only a minimal risk of a substantial material flow, the work plan can be developed without further engineering input. Work of this type generally involves powered excavating equipment that is substantial in size and affords protection for the operator in the event of any mifnor material flow. If there is a danger of logs, trees or other debris coming down the slope, operators of mobile equipment must be protected by suitable cabs, screens, grills, shields, guards or structures (see section 16.21 of the OHS Regulation). It is necessary that such operations be carried out, as far as is practicable, so that the height of any unstable face being worked does not exceed the maximum safe reach of the excavating equipment being used (see section 20.93 of the OHS Regulation).

Pedestrian workers should stay clear of the working face, any other unstable faces, and operating equipment.

Rock scaling
Rock scaling is a form of excavation, but is not generally an activity that will change the cross section profile of a slope. Scaling of slopes is not an activity normally considered within the scope of section 20.78, and is specifically addressed in sections 20.96 to 20.101 of the OHS Regulation. If there is a concern regarding the overall stability of a slope that is to be scaled, an engineering assessment and instructions should be obtained and followed.

G20.78(2) Engineering documents

Issued August 1999; Editorial Revision February 2006

Section 20.78(2) states "The written instructions required in subsection (1) must
(a) be certified by a professional engineer,
(b) be available at the site, and
(c) specify the support and sloping requirements, and the subsurface conditions expected to be encountered".

Verbal instructions from an engineer with no supporting documents are insufficient.

The following should be included as a minimum for an engineering certificate on a site under this section:

date of issue,
site address/location,
drawing/sketch, plan and sections and/or clearly written instructions,
geotechnical description of the expected soil conditions, or confirmation upon site review,
limitations for machinery or equipment being adjacent to the excavation,
time period for which certification applies,
influence of changing weather conditions, and
name of the certifying engineer, signature and seal.

Subsequent certifications may refer back to the initial certification documents, in which case such documents must be available at the site. If conditions and/or instructions change with respect to the conduct of the excavation work, supplementary instructions and documentation are required.

If the engineer's certification is incomplete or deemed inadequate, work should stop in the hazard area until acceptable certification is available, or until remedial work done so that the excavation complies with the OHS Regulation.

G20.79 Underground utilities

Issued August 1999; Editorial Revision August 2004; Revised February 13, 2006

Regulatory excerpt

Section 20.79 of the OHS Regulation states:

(1) Before excavating or drilling with powered tools and equipment, the location of all underground utility services in the area must be accurately determined, and any danger to workers from the services must be controlled.

(2) Excavation or drilling work in proximity to an underground service must be undertaken in conformity with the requirements of the owner of the service.

(3) Pointed tools must not be used to probe for underground gas and electrical services.

(4) Powered equipment used for excavating must be operated so as to avoid damage to underground utility services, or danger to workers.

Section 4.18 of the OHS Regulation states:

An employer whose work activities result in a hit or damage to a pipeline, buried electrical cable or other such utility must notify the owner of the utility without delay.

Purpose of guideline
The purpose of this guideline is to

reference the practice document related to the requirements under section 20.79 of the OHS Regulation
highlight some jurisdictional considerations
explain the occupational health and safety obligations of employers when their work activities result in a hit or damage to a pipeline, buried electrical cable or other such utility

Practice document
Prevention of Damage to Buried Facilities in British Columbia (www.worksafebc.ca/publications/health_and_safety/by_topic/assets/ pdf/buried_facilities_bk90.pdf) provides practices and procedures for excavating near buried facilities. The information in the document should be considered in conjunction with applicable legislation and regulations.

Other legislation governing excavations near underground utilities
Jurisdictions other than WorkSafeBC also have statutes and regulations that apply to excavation or drilling in proximity to an underground utility service. For example, the Gas Safety Regulation (http://www.qp.gov.bc.ca/statreg/reg/S/103_2004.htm) specifies the means by which excavators who work near a gas installation must determine the existence of underground gas services and the methods that excavators must use to find the exact location of services.

See Prevention Manual Policy Item D1-108-1 Application of Part 3 - Where Jurisdictional Limits Exist (www2.worksafebc.com/Publications/OHSRegulation/Policies-WorkersCompensationAct.asp#SectionNumber:D1-108-1) for guidance on how WorkSafeBC prevention officers will exercise their powers in situations where there are jurisdictional limits on those powers.

OHS Regulation requirements if contact with any underground facility occurs
Notify the owner of the utility without delay
Section 4.18 of the OHS Regulation requires an employer, whose work activities result in a hit or damage to a pipeline, buried electrical cable, or other such utility, to notify the owner of the utility without delay.

Notify WorkSafeBC where required
Damage to underground facilities can cause death or serious injury to a worker. Section 172 of the Workers Compensation Act ("Act") specifies the accidents that an employer must immediately report to WorkSafeBC, including any accident that results in serious injury or death of a worker, or involves the major release of a hazardous substance.

An important factor in determining whether there is a major release of a hazardous substance is the seriousness of risk to the health of workers that the release presents. Policy includes some factors that determine the seriousness of the risk. Situations involving natural gas that should be considered a "serious risk" include the following:

it was necessary for people to be evacuated from buildings
gas seeped into sewers or drains
any person required medical treatment
the gas leak ignited
repair workers entered the gas envelope when the atmosphere contained flammable gas or vapor concentrations in excess of 20% of the lower explosive limit (LEL)
a non-gas company worker entered an excavation, after a strike, to attempt to stop or slow the flow of gas

Policy Item D10-172-1 Accident Reporting and Investigation - Immediate Notice of Certain Accidents (Major Release of Hazardous Substance) (www2.worksafebc.com/Publications/OHSRegulation/Policies-WorkersCompensationAct.asp#SectionNumber:D10-172-1) discusses the meaning of the "major release of a hazardous substance" under section 172.

Investigate the incident
Under section 173 of the Act employers must immediately undertake an investigation into the cause of any accident or incident that had a potential for causing serious injury to a worker. Any gas line hit or high voltage contact is likely to fall into this category and an investigation is required.

Also, under section 173 of the Act the employer must investigate the occurrence of any accident that involved the major release of a hazardous substance. See section 173 of the Act for additional incidents that employers must investigate.

G20.81 Sloping and shoring requirements

Issued August 1999; Editorial Revision August 31, 2007

Regulatory Excerpt
Section 20.81(1) of the OHS Regulation ("Regulation") states:

Before a worker enters any excavation over 1.2 m (4 ft) in depth or, while in the excavation, approaches closer to the side or bank than a distance equal to the depth of the excavation, the employer must ensure that the excavation sides are sloped or supported as specified by a professional engineer, or that the sides of the excavation are

(a) sloped at angles, dependent on soil conditions, which will ensure stable faces, but in no case may the slope or combination of vertical cut and sloping exceed that shown in Figure 20-1,

(b) benched as shown in Figure 20-2,

(c) supported in accordance with the minimum requirements of section 20.85, or

(d) supported by manufactured or prefabricated trench boxes or shoring cages, or other effective means.

Purpose of guideline
The purpose of this guideline is to provide explanatory material for the Regulation requirements in sub-sections 20.81(a)-(d).

Explanatory information for sub-sections 20.81(a)-(d)
This section is subject to section 20.78, which requires engineering certification in certain situations.

"Excavation" is defined in section 20.1 as meaning any "cut, cavity, trench or depression in the earth's surface resulting from rock or soil removal". This includes, for example, a hole dug in the ground, as well as the cutting of material away from a slope, such as occurs on roadway construction.

Section 20.81 requires that one of clauses (a) to (d) be met in all cases where an excavation over 4 feet deep has a width that is equal to or less than twice its depth. If the excavation is wider than twice its depth, this will only have to be done if the worker will approach "closer to the side or bank than a distance equal to the depth of the excavation". The latter includes situations where there is no measurable width because the excavation is, for example, a cut into a slope. In these situations, the worker must enter and exit the excavation by a safe route, for example, a properly sloped or shored portion of the excavation.

Section 20.81(1)(c) refers to section 20.85. Section 20.85, and by reference Table 20-1, contain detailed specifications for "trench support structures". A "trench" is defined in section 20.1 as "an excavation less than 3.7 m (12 ft) wide at the bottom, over 1.2 m (4 ft) deep, and of any length". Section 20.81(1)(c) and section 20.85 do not apply to excavations over 12 feet wide, or excavations that have no measurable width.

Section 20.81(1)(d) permits the use of manufactured or prefabricated trench boxes or shoring cages. These may be used in accordance with the manufacturer's instruction or engineering certification for the device, unless the instructions for use do not adequately include the circumstances of use or questions arising at the site, or where the situation is covered in the scope of section 20.78(1). The instructions for use and/or certification of a trench box or cage should specify the types of soil conditions for which it is intended and the instructions relating to each. A copy of this information should be on site.

Section 20.81(1)(d) also permits the use of "other effective means". Section 20.78(1)(b) requires an engineer's certification if "support structures other than as specified in section 20.81 are used in the excavation". The latter covers any method of shoring other than the "manufactured or prefabricated trench boxes or shoring cages" referred to in section 20.81(d) and the trench support structures for which specific requirements are set by section 20.85.

G20.85 Trench support structures

Issued August 1999

Section 20.85 of the OHS Regulation and its accompanying tables and figures set out detailed requirements for trench support structures required under section 20.81(1)(c). Any trench support structures not covered by these requirements, other than "manufactured or prefabricated trench boxes or shoring cages" allowed by section 20.81(d), must be covered by a professional engineer's certificate under section 20.78(1)(b).

The requirements of section 20.85 depend on the type of soil. Type A soil is described in the section as "hard and solid". No soil is type A if it:

is fissured,
is subject to vibration from heavy traffic, pile driving or similar effects,
has been previously disturbed,
is part of a sloped or layered system where the layers dip towards the excavation on a slope of 4H:1V or greater, or
the material is subject to factors that would require it to be classified as a less stable material.

Type C soil is described in section 20.85 as "soft, sandy, filled or loose". It typically has a low, unconfined compressive strength. It can be

a granular soil, including gravel, sand and loamy sand,
submerged soil or soil from which water is freely seeping,
submerged rock that is not stable, or
material in a sloped, layered system where the layers dip towards the excavation on a slope of 4H:1V or greater.

A more detailed, technical classification of soil types is available in OSHA Subpart P, Appendix A. Visual and testing parameters are provided for analysis.

Combination of sloping and shoring
Section 20.85(2) and Figure 20-3 specify an option if a combination of sloping and shoring is to be used. The following additional information may help clarify the relationship between H, the 1:1 slope and the 1.5H horizontal dimension in Figure 20-3. If the broken reference line extending on a 1:1 slope from the toe or base of the excavation meets the surface of undisturbed ground within a distance of 1.5 times the depth of the trench, the trench support structures specified by section 20.85 can be used. If not, the original ground slopes upward steeper than a 1 vertical in 3 horizontal slope, and a professional engineer's certificate must be obtained under section 20.78(1)(b) and followed.

Guidelines Part 20 - Marine construction, pile driving and dredging

G20.102 Suspended work platforms in marine construction and pile driving activities

Issued May 17, 2006

Regulatory excerpt
Section 20.102 of the OHS Regulation states:

(1) Suspended work platforms such as gilley boards, small boats and buckets used to support workers must meet the requirements for suspended work platforms in Part 13 (Ladders, Scaffolds and Temporary Work Platforms).
(2) Despite section 13.27(5), a secondary hoisting line on a crane may be used to suspend workers on a work platform in a marine construction or pile driving operation if

(a) it is not practicable to provide another means for positioning workers to perform work tasks,

(b) all the crane's hoisting gear that is being used conforms to section 13.29(1), and

(c) the total load attached to or suspended from all load lines of the crane does not exceed 50% of the rated capacity of the crane for the reach and configuration.

Purpose of guideline
This guideline provides information on the circumstances under section 20.102(2)(a) in which WorkSafeBC expects it will be practicable to use a second crane or other hoist as a means for positioning workers to perform work tasks, and when it will not be practicable. The term "practicable" is defined in the OHS Regulation to mean "that which is reasonably capable of being done." The guideline also provides information on the application of section 20.102(2)(b).

Practicability of using a second crane or other hoist
The issue of practicability varies somewhat depending on whether the operations are done using equipment based on the ground or a dock, or are performed using equipment based on a barge, scow, or similar floating support.

Operations where equipment is used on the ground or a dock: It is generally considered practicable to use a second crane, a boom-supported elevating work platform, or other safe means to position workers to do tasks at height unless the area does not provide sufficient space or there are conditions that do not permit safe positioning of additional equipment. Examples of such cases include operations done on ground where access is limited or soil conditions preclude the use of additional equipment, and those done from a narrow wharf, jetty, or dock area with substantial space restrictions.

If the space is adequate for the operation of a second crane or other hoisting device, it may still not be practicable to bring in the second piece of equipment if the work is extremely short in duration or involves only a few lifts and is incidental to the job. Two examples are noted below.
- The work is solely for the purpose of routine maintenance on the crane, pile driver, or leads. For example, if it is necessary to re-thread a pile line on the leads, or to access the upper sheaves of the crane for maintenance such as lubrication, the use of a work platform suspended on a second load line while the pile driver and/or leads remain supported by another load line of the crane is considered normal and acceptable practice.
- During marine construction and pile driving work there may be other short duration lifting tasks that need to be done, for example the top of a light standard may need to be installed or removed. For such tasks the pile driver and leads are disconnected from the crane, rendering the crane available for use in its usual or normal configuration, with one load line supporting workers in a platform and the other line used to position or support the part to be installed or removed.
  
  However, if such crane tasks are more than incidental, for example the work will take more than a day, and equipment such as a second crane or a boom-supported elevating work platform is reasonably available to the site, WorkSafeBC expects the work to be planned and executed in a manner that complies with section 13.27(5).
Operations where equipment is used on a barge or scow: It is generally considered not to be practicable to use a second crane to lift a work platform or use an elevating work platform when operations are done from a barge, scow or similar floating equipment.

For example, if the secondary equipment is placed on the same barge or scow there usually will not be sufficient space to safely position the equipment. Also, in the case of an elevating work platform, it may not be possible to assure that the elevating work platform carrier will remain level within the limits normally required for safe operation of such equipment, in circumstances where there is listing of the barge or scow resulting from loads being handled by the crane, or as a result of wind and wave action.

If the secondary equipment is placed on another barge or scow, or on a nearby dock or land area there may be hazards to workers created from the relative movement of the two pieces of lifting equipment, as a result of the listing of the barge or scow from loads being handled by the crane, or from wind and wave action.

Intention of section 20.102(2)(b)
This provision references section 13.29(1) of the OHS Regulation, and broadens the application of the requirements under that section to all hoisting gear, including the primary line, the line used to lift workers and, where applicable, the boom hoist. In other words, all hoisting lines must be operated as slowly as practicable when workers are being lifted on the platform and must be lowered under power, and no line may be used with a free running boom or hoisting winch controlled only by brakes. Section 13.29(2) and (3) continue to apply, but only to the line used to lift workers.

Guidelines Part 20 - Demolition

G20.112 Hazardous materials - Asbestos

Preliminary Issue June 18, 2008

Regulatory excerpt
Section 20.112 of the OHS Regulation ("Regulation") states:

Before work begins on the demolition or salvage of machinery, equipment, buildings or structures, the employer or owner must

(a) inspect the site to identify any asbestos, lead, or other heavy metal or toxic, flammable or explosive materials that may be handled, disturbed or removed,

(b) have the inspection results available at the worksite, including any drawings, plans or specifications, as appropriate, to show the locations of any hazardous substances,

(c) ensure that any hazardous materials found are safely contained or removed, and
(d) if hazardous materials are discovered during demolition work that were not identified in the inspection required by paragraph (a), ensure that all work ceases until such materials are contained or removed.

Purpose of guideline
Demolition and salvage work involve the taking apart and destruction, in whole or in part, of buildings, structures, equipment, and machinery. These processes have the potential to create harmful exposures to hazardous materials. Regulation section 20.112 names several types of hazardous materials which must be identified and either safely contained or safely removed prior to demolition or salvage work. Asbestos is one of these materials.

The purpose of this guideline is to explain the hazards associated with the uncontrolled release of asbestos. It also provides information for owners, employers, consultants, workers and other involved persons on what constitutes a compliant asbestos inspection, arranging for and confirming the safe abatement of asbestos, and what to do if additional materials suspected to contain asbestos are encountered during demolition or salvage work.

Note: Demolition work is often a necessary component of a building renovation project or restoration work following a fire or flood, and the requirements of section 20.112 of the Regulation and the information in this guideline also apply when demolition work is part of building renovation or restoration.

Background information
Demolition and salvage work, if performed incorrectly, can create harmful dust exposures to a variety of workers and other persons, including owners, developers, demolition workers, inspectors, transportation workers, landfill workers, and the public. If demolition of a house/building proceeds without first ensuring identification and safe removal of the asbestos hazards, asbestos dust can be released, and remain airborne for a long period of time, potentially exposing workers. During the demolition of the interior walls and ceilings, the demolition or salvage workers may then be exposed to airborne asbestos fibres in the dust from the gypsum board filling compound (sometimes called drywall mud) and from textured ceilings and walls. Vermiculite attic insulation containing asbestos fibres can spill out of the attic when the ceiling material is removed. Asbestos-containing dusts from these demolition activities can contaminate the site and disperse to neighbouring properties exposing other persons. As demolition debris is loaded into a disposal truck the excavator operator and the truck driver can be exposed to asbestos containing dusts which can also drift into neighboring properties. As the disposal truck travels to the landfill site, dust that contains asbestos can blow out of the truck, spreading asbestos dust along its travel route. When the truck discharges its asbestos contaminated load at the landfill, unprotected landfill site workers can be exposed to the airborne hazard. These demolition practices are unacceptable and non compliant with the Regulation.

Asbestos hazards must be controlled through identification and safe abatement of asbestos, by trained persons, before demolition. This guideline provides information for acceptable identification, assessment, reporting, and removal of asbestos hazards in buildings and structures slated for demolition (refer also to the "Ten Steps to Compliance" chart at the end of this guideline).

The requirements in Regulation section 20.112 are related to other requirements in both the Regulation and the Workers Compensation Act ("Act"). For example, when asbestos is removed, other requirements in Regulation Part 6-Asbestos are also applicable. The requirements in sections 115 (General duties of employers) and 119 (General duties of owner) in the Act also apply.

More information related to asbestos hazard assessment and control measures for building demolition can be found in

(1) OHS Guideline G6.8 "Procedures for abatement of asbestos materials during house and building demolition/renovation"
(2) WorkSafeBC publication BK27 "Safe Work Practices for Handling Asbestos" (PDF 1 mb)
(3) WorkSafeBC hazard bulletin WS03-03 "Asbestos Hazards in Demolition, Renovation and Salvage" (PDF 204 kb)
(4) WorkSafeBC bulletin WS2008-03 "The dangers of exposure to asbestos in vermiculite attic insulation" (PDF 1 mb)

Responsibilities and Qualifications
Regulation section 20.112 specifies explicit responsibilities for the owner and the employer. As per the Act section 124, these parties need not duplicate the same compliance efforts providing they coordinate their actions to ensure that compliance with all provisions of section 20.112 is achieved.

Prior to asbestos removal occurring, the owner or prime contractor must ensure that a Notice of Project (NOP) for asbestos, including detailed written safe work procedures, as required under Regulation section 20.2, is submitted to WorkSafeBC at least 24 hours in advance of the asbestos removal occurring. An asbestos risk assessment must be done by a qualified person (see Regulation section 6.6) and the assessment report should accompany the NOP for asbestos. A qualified person is described and explained in OHS Guideline 6.6-3.

In addition to conducting the risk assessment and work activity classification, the following activities should also be conducted by the qualified person:

Identification of asbestos
Preparation of asbestos work procedures
Collection of samples of materials suspected of containing asbestos
Completion of the asbestos survey report
Collection and interpretation of air samples during asbestos abatement projects
Preparation of inspection reports
Conduction of workplace inspections

Inspection for and Identification of any asbestos
Regulation section 20.112(a) requires that before work begins on the demolition or salvage of machinery, equipment, buildings, or structures, the employer or owner must inspect the site to identify any asbestos that may be handled, disturbed, or removed. This is separate from an inventory required by section 6.4 of the Regulation. The inventory prepared under section 6.4 is required for the protection of workers who may occupy a building. Although it may not include asbestos that wasn't readily accessible (e.g. hidden behind concrete walls or under a number of layers of flooring), the inventory required by section 6.4 will be a useful aid in conducting the inspection specified in section 20.112. The inspection required by section 20.112 will locate and identify all asbestos prior to renovation and demolition activities.

Any asbestos includes, but is not limited to, asbestos-containing material as defined in Regulation section 6.1, and is not limited to materials that contain 1% or greater asbestos content. Any asbestos includes materials, such as vermiculite insulation, that may contain less than 1% asbestos and which have the potential to create harmful exposures to workers if these materials are disturbed in an uncontrolled manner. The ALARA principle applies. ALARA means, in reference to a designated substance like asbestos, that measures must be taken to keep a worker's exposure to a level as low as is reasonably achievable below the exposure limit.

The asbestos inspection process is referred to as a pre-renovation or pre-demolition asbestos survey and the person conducting the inspection is often referred to as the surveyor. The asbestos survey includes a walk-through inspection, sample collection, sample analysis, reporting and communicating the results. Surveyors must be familiar with proper walk-through and sample collection practices. There are a number of recognized industry standards which provide guidance on conducting asbestos surveys, and include the following:

(1) The Ontario Regulation 278/05 Designated Substance - "Asbestos on Construction Projects and in Buildings and Repair Operations"

(2) MDHS 100 "Surveying, Sampling and Assessment of Asbestos-Containing Materials" HSE Health and Safety Executive in the U.K. (PDF 774 kb)

(3) EPA How to Manage Asbestos in School Buildings EPA 910-B-96-001 (PDF 653 kb)

The first step in the asbestos survey is to identify asbestos hazards by a thorough and systematic walk-through inspection of the site. The site may be a building (commercial, industrial, residential), a structure, a machine, or a piece of equipment. Asbestos identification and recognition is a specialized skill and it is essential that the surveyor be adequately instructed, trained, and experienced in identifying materials known to, or likely to, contain asbestos.

Table 1 lists some of the materials that commonly contain asbestos in older commercial and residential buildings.

Table 1: Asbestos Materials in Commercial and Residential Buildings

Exterior	Interior insulation
Asbestos cement pipes (e.g., drain pipes) Roof felting Asphalt shingles Soffit boards Stucco Asbestos cement siding Brick mortar Window putty Deck undersheathing Asbestos cement shingles	Spray-applied insulation (acoustic and fireproofing) Vermiculite (blown-in) insulation (e.g., in attics) Paper backing on fibreglass insulation
Flooring	Heating (HVAC) and ducting
Vinyl sheet flooring and mastic Vinyl floor tile and mastic Poured flooring/leveling compound Asphalt flooring	Furnace duct tape Furnace/boiler insulation Pipe (mechanical) insulation Hot water tank insulation Mastic Asbestos rope and gaskets Asbestos cement board Asbestos cardboard insulation
Walls & Ceilings	Other
Drywall mud Plaster Asbestos cement board Textured coatings Ceiling tiles	Fireplace box and mantel Artificial fireplace logs and ashes Fire doors Insulation on electrical wiring Fire blankets Chalk boards Heat reflectors Penetration firestopping Candescent light fixture backing (pot lights)

Note: This list does not include every product that may contain asbestos. It is intended as a general guide (see also the online WorkSafeBC Bulletin WS 03-03 (PDF 274 kb)).

During the initial walk-through inspection the surveyor systematically goes through each area and room in the building observing the wall, ceiling, floor, and other materials including any machinery or equipment (e.g. an old boiler or HVAC system) and hidden insulating materials to make a preliminary determination if asbestos could be present. During this walk-through, the surveyor will also consider where to collect representative bulk samples of suspect asbestos material. Once the walk-through is complete, the surveyor has the necessary information to begin the sampling process (see next section).

The following Asbestos Inspection Results worksheet (and example completed worksheet) (PDF version 148 KB) illustrates an acceptable method by which asbestos survey results can be summarized for an owner or contractor.

Asbestos Inspection Results
Project Name:				Date of Survey:
Address:				Survey Company:
Description:				Surveyor:
Previous Renovation

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Guidelines Part 20

Guidelines Part 20 Contents

DEFINITIONS

GENERAL REQUIREMENTS

SAFE WORK AREAS AND SAFE ACCESS

CONCRETE FORMWORK AND FALSEWORK

CONCRETE PUMPING

OPEN WEB JOISTS AND TRUSSES

ROOF WORK

EXCAVATIONS

MARINE CONSTRUCTION, PILE DRIVING AND DREDGING

DEMOLITION

Guidelines Part 20 - Definitions

G20.1 Construction project-routine maintenance

Guidelines Part 20 - General requirements

G20.2(1)(a) Notice of project

G20.2(1)(f) Bell holes

Guidelines Part 20 - Safe work areas and safe access

G20.4(1) Suitable ladders, work platforms, and scaffolds

G20.4(2) Suitable access for safe delivery of equipment and materials

G20.9 Protection from falling materials

G20.13(3.1) Ensuring loads do not exceed capacity of thrust-out platforms

Guidelines Part 20 - Concrete formwork and falsework

G20.26 Inspections

Guidelines Part 20 - Concrete pumping

G20.40 Use of outriggers on concrete pumping equipment

G20.47 Inspection and certification of concrete placing booms and masts

Guidelines Part 20 - Open web joists and trusses

G20.72 Erection instructions

Guidelines Part 20 - Roof work

G20.75 Fall protection

G20.77 Mechanical equipment

Guidelines Part 20 - Excavations

G20.78(1) Vibration, hydrostatic pressure and hazardous ground movement

G20.78(1)(e) Ground slope adjacent to excavation work

G20.78(2) Engineering documents

G20.79 Underground utilities

G20.81 Sloping and shoring requirements

G20.85 Trench support structures

Guidelines Part 20 - Marine construction, pile driving and dredging

G20.102 Suspended work platforms in marine construction and pile driving activities

Guidelines Part 20 - Demolition

G20.112 Hazardous materials - Asbestos