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Guidelines Part 13

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Guidelines Part 13 Contents

DIVISION 1 - GENERAL

  G13.1 Types of work platforms
  G13.2 Standards acceptable to WorkSafeBC
  G13.2(1) Ship's ladders
  G13.2(1)(b) Ladders in manholes
  G13.2(1)-2 Application of CSA and ANSI standards for suspended stages

DIVISION 2 - LADDERS

  G13.4 Ladder ratings and selection

DIVISION 3 - WORK PLATFORMS

  G13.8 General requirements - Chair Design

DIVISION 4 - SCAFFOLDS

  G13.14 Guardrails on end frame scaffolds
  G13.19 When and how to ground metal scaffold

DIVISION 5 - MOVABLE WORK PLATFORMS

  G13.23(1) Inspection and certification of elevating work platforms
  G13.25 Warning devices
  G13.29 Lower travel limit devices
  G13.30 Work platforms supported by a lift truck
  G13.32 Prior permission - Platform use in high risk situations

Guidelines Part 13 Division 1 - General

G13.1 Types of work platforms

Issued January 1, 2005; Revised March 8, 2007

Regulatory excerpt
Section 13.1 of the OHS Regulation ("Regulation") includes the following definitions:

"boom-supported" means supported by an elevating device that telescopes, articulates, rotates or extends relative to the machine base or vehicle, so that the platform can be positioned completely beyond the base;

"boatswain's chair", also known as a bosun's chair, means a seat attached to a suspended rope designed to accommodate one person in a sitting position;

"elevating work platform" means a movable work platform that self-elevates to overhead work locations;

"movable work platform" means a work platform that can be re-positioned during the course of the work;

"permanent powered platform" means a movable work platform that
(a) is raised or lowered by other than manual means, and
(b) is permanently installed on or attached to a building or structure;

"portable powered platform" means a movable work platform that
(a) is raised or lowered by other than manual means, and
(b) is not permanently installed on or attached to a building or structure;

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

"self-propelled" means the capability of an elevating work platform to travel under power with the primary controls on the work platform;

"swing stage" means a work platform that is raised and lowered by manual or powered hoisting equipment, supported by 2 or more suspension lines;

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

Purpose of guideline
This guideline provides a chart to show the various types of work platforms covered by Part 13 of the Regulation, and a brief explanation of some types of movable platforms.

Chart - Types of work platforms

Chart shows two different types of work platforms: scaffolding, and movable work platforms. Movable work platforms are divided into three different categories: suspended staging, elevating work platforms, and platforms supported by other equipment. Explanations of terms are provided below.

Explanation of terms
Confusion sometimes arises about the differences between some of the terms in the chart, particularly related to movable work platforms. The following explanations are intended to assist the reader.

Movable work platforms: A movable work platform is a platform that can be moved, manually or by power, in either the vertical or horizontal direction, or both, and covers a range of types of equipment. The different types of movable work platform shown in the chart can be discussed in three groups: suspended staging, elevating work platforms, and platforms supported by other equipment.

  • Suspended staging (permanent powered platforms, swing stages, and boatswain's chairs): These are all movable platforms that are supported by line(s) from a building or structure, and can be repositioned vertically during use.

  • Elevating work platforms: An elevating work platform is one that self-elevates, and includes design features for lateral mobility (travel). If the platform travels under power when operated by controls on the work platform it is termed "self propelled." There are two types of self propelled units, those that are boom supported, and other designs, such as self-propelled scissor lifts.

    Alternatively, if an elevating work platform is moved by hand or is attached to the deck of a powered vehicle, it is called a "portable elevating work platform." There are a range of types of portable elevating work platforms in use, from elevating equipment mounted on service trucks, to compressed gas power lifts that are moved by hand. Mast climbers that provide access to the face of a building, and that can be repositioned vertically as work proceeds are also included in this group.

  • Platforms supported by other equipment (lift truck supported, and crane or hoist supported): A platform that is elevated by another piece of equipment is not an elevating work platform, because the platform itself is not designed to be capable of elevating. Examples of this type of work platform are those that are positioned and supported by a crane, hoist, or lift truck. These platforms are movable, but they are not elevating.
G13.2 Standards acceptable to WorkSafeBC

Issued January 1, 2005; Editorial Revision May 2005; Editorial Revision August 12, 2008; Editorial Revision September 1, 2009

Regulatory excerpt
Section 13.2(1) of the OHS Regulation ("Regulation") states:

A ladder, window cleaner's belt or work platform must meet and be used in accordance with

(a) the applicable CSA or ANSI standard in effect when the equipment or structure was manufactured, except as otherwise determined by the Board,

(b) another standard acceptable to the Board, or

(c) if there is no applicable standard under paragraphs (a) or (b), the requirements of a professional engineer.

Purpose of guideline
The purpose of this guideline is to provide a list of some common applicable standards for ladders, scaffolds, and temporary work platforms that are acceptable to WorkSafeBC under section 13.2(1).

List of applicable standards acceptable under section 13.2(1)
Agency Standard number Standard title
CSA1B354.1 Portable Elevating Work Platforms
CSAB354.2 Self-propelled Elevating Work Platforms
CSA B354.4 Self-propelled Boom-Supported Elevating Work Platforms
CSA C225 Vehicle-Mounted Aerial Devices
CSA S269.2 Access Scaffolding for Construction Purposes
CSA Z11 Portable Ladders
CSA Z91 Health and Safety Code for Suspended Equipment Operations
CSA Z185 Safety Code for Personnel Hoists
CSA Z271 Safety Code for Suspended Elevating Platforms
CSA Z323.5 Mechanical/Electromechanical Lifting Devices for Persons
WCB2 WPL2-2004 Design, Construction and Use of Crane Supported Work Platforms
WCB LDR1-2004 Job Built Ladders
WCB WPL3-2004 Safety Factor and Minimum Breaking Strength for Suspended Work Platforms and Associated Components
WCB WPL1-2004 Design, Construction and Use of Wood Frame Scaffolds
WCB WorkSafeBC13.30 Work Platforms supported by Lift Trucks
ANSI3 A10.22 Safety Requirements for Rope-Guided and Non Guided Workmen's Hoists
ANSIA10.8American National Standard for Construction and Demolition Operations - Scaffolding - Safety Requirements
ANSI A120.1Powered Platforms for Exterior Building Maintenance
ANSI A14.1 Safety Requirements for Portable Wood Ladders
ANSI A14.2 Safety Requirements for Portable Metal Ladders
ANSI A14.3 American National Standard for Ladders - Fixed - Safety Requirements
ANSI A14.5 Safety Requirements for Portable Reinforced Plastic Ladders
ANSI A14.7 Safety Requirements for Mobile Ladder Stands and Mobile Ladder Stand Platforms
ANSI A39.1 Safety Code for Window Cleaning
ANSIA92.1Mobile Ladder Stands and Scaffolds (Towers), Manually Propelled
ANSIA92.2Vehicle-Mounted Elevating and Rotating Aerial Devices (Work Platforms)
ANSI A92.3 American National Standard for Manually Propelled Elevating Aerial Platforms
ANSI A92.5 Boom-Supported Elevating Work Platforms
ANSI A92.6 American National Standard for Self-propelled Elevating Work Platforms
ANSI A92.8 American National Standard for Vehicle-Mounted Bridge Inspection and Maintenance Devices
ANSI A92.9 American National Standard for Mast-Climbing Work Platforms
ASME4 B30.23 Personnel Lifting Systems
ANSI B56.1 Safety Standard for Low Lift and High Lift Trucks
ANSI B56.6 Safety Standard for Rough Terrain Forklift Trucks
ANSI A14.4 Job-Made Ladders, Safety Requirements for
ASTM5 C 478M Standard Specification for Precast Reinforced Concrete Manhole Sections

1CSA: Canadian Standards Association
2WCB: WorkSafeBC (Workers Compensation Board of British Columbia)
3ANSI: American National Standards Institute
4ASME: American Society of Mechanical Engineers
5ASTM: American Society for Testing and Materials

G13.2(1) Ship's ladders

Issued May 25, 2005

Regulatory excerpt
Section 13.2(1) (Standards) of the OHS Regulation states:

(1) A ladder, window cleaner's belt or work platform must meet and be used in accordance with

(a) the applicable CSA or ANSI standard in effect when the equipment or structure was manufactured, except as otherwise determined by the Board,

(b) another standard acceptable to the Board, or

(c) if there is no applicable standard under paragraphs (a) or (b), the requirements of a professional engineer.

Purpose of this guideline
This guideline sets out the circumstances where a "ship's ladder" would normally be acceptable for use. It also provides guidance on the expectations of the Board for the design, installation and use of such a ladder.

What is a ship's ladder?
A ship's ladder, as addressed by this guideline, means a permanently installed steep pitched stair-like structure having rigid treads supported by rigid side rails, with handrails on each side. It does not include a ladder configuration made of treads or rungs supported by "side rails" made of fibre or wire rope. While the ladder is referred to as a ship's ladder, the usage covered in this guideline is with respect to land-based applications as described below.

Where are they appropriate?
A ship's ladder should only be considered for use where a conventional stairway cannot be installed due to limited space. Installation should be limited to places where only occasional use is required, such as for servicing machinery or equipment on a typical frequency of less than daily.

There is no CSA or ANSI standard that has been issued to address ship's ladders. In the absence of a standard the Board has a number of expectations for the design, installation and use of these ladders under section 13.2(1) of the OHS Regulation, which are outlined below.

Ladder design and installation
A ship's ladder should:

  • be designed so the angle between the side rails and the horizontal is between 50 and 70 degrees. The preferred angle is in the range of 60 to 68 degrees.
  • serve only a single platform or landing and have a maximum height of 4 metres (12 feet)
  • have treads at least 130 millimetres (mm) (5 inches) wide, with a nonskid finish, uniformly spaced at not more than 305 mm (12 inches). Treads should be at least 430 mm (17 inches) long, but not longer than 630 mm (24 inches).
  • have a minimum design working load of 1.1 kiloNewtons (kN) (250 pounds) applied uniformly to a 90 mm (3.5 inch) strip across the centre of the tread
  • have handrails provided on both sides of the ladder at approximately 900 mm (36 inches) above the tread nosing
  • have a safety guard installed parallel to the slope of the ladder and offset approximately 150 mm (6 inches) from the rear of the treads. (This guard is to stop a worker's leg from passing through to the backside of the ladder if a foot slips off the back side of the tread.)

Note that a ship's ladder is a permanent load-carrying structure and needs to be properly engineered, as required by section 13.2(1)(c). Design drawings and specifications should show all information necessary for the fabrication and installation of the ship's ladder, including details on how it is to be secured in place. The completed installation will need to be certified by a professional engineer as being fabricated and installed in accordance with good engineering practice.

Ladder use
The user of a ship's ladder should:

  • be trained on the correct way to use the ladder
  • face the ladder when ascending or descending
  • have both hands free to grasp the handrails when using the ladder. Tools or other items which prevent both hands from being free to grasp the handrails should not be carried up or down the ladder.
  • maintain "three points of contact" when using the ladder. Three points of contact means two feet and one hand or two hands and one foot in contact with the ladder and handrails at all times. (This is recommended practice when using any type of ladder.)
G13.2(1)(b) Ladders in manholes

Issued January 1, 2005

Section 13.2(1) of the OHS Regulation states:

(1) A ladder, window cleaner's belt or work platform must meet and be used in accordance with

(a) the applicable CSA or ANSI standard in effect when the equipment or structure was manufactured, except as otherwise determined by the Board,

(b) another standard acceptable to the Board, or

(c) if there is no applicable standard under paragraphs (a) or (b), the requirements of a professional engineer.

This guideline sets out a standard acceptable to the Board for the design and construction of an individual rung ladder in a manhole that is part of a water, sewer or storm sewer system. These manholes typically have an outside diameter of 48 inches or less, and may have a tapering cone section near the top. For these structures it is recognized that the amount of interior space for access and to perform work is limited and the access ladder arrangement needs to provide for safe access while not protruding unnecessarily into the entry and work space. The Board recognizes the ASTM Specification C 478M Standard Specification for Precast Reinforced Concrete Manhole Sections as a standard acceptable to the Board under section 13.2(1)(b) for an individual rung ladder in such manholes. (Note this version is the metric companion to ASTM Specification C 478, which is also acceptable to the Board.) This standard refers to an individual rung as a "step".

ASTM Specification C 478M was developed for manholes assembled using precast concrete components for the base, riser, cone, and top sections. Manholes are also assembled using components for these sections made from other materials. Manhole steps or individual rungs will be cast, mortared or attached by mechanical means to the walls of base, riser or cone sections. Steps or rungs in a manhole must meet the design, material, dimension, and testing and acceptance criteria of the ASTM Specification C 478M, regardless of the material used to make the risers or cone sections.

ASTM Specification C 478M requires steps in a manhole's base, riser(s) and conical top section be aligned to form a continuous ladder with steps (rungs) equally spaced vertically at a maximum spacing of 400 millimetres (16 inches). Rungs must project a minimum clear distance of 100 millimetres (4 inches) from the wall of the base, riser or cone section measured at the point of embedment or attachment. The minimum clear distance between the rung and the opposite wall of the riser or cone must be 450 millimetres (18 inches) measured at the centre face of the rung. The minimum width of a step or rung is 250 millimetres (10 inches).

The maximum distance down from the entry level (rim of the manhole cover) to the centerline of the first rung below entry level in any manhole should be 500 mm (20 inches) where no handhold is provided above the first rung. Where a handhold is provided between the entry level and the first rung, the maximum distance may be increased to not more than 660 mm (26 inches).

ASTM Specification C 478M does not require any additional ladder safety features, such as a cage, rest platform or ladder climbing device, regardless of the length of climb. Safety cages and rest platforms should not be used in a manhole as they may impede rescue or retrieval procedures. A worker entering a deep manhole, such as one more than 5 metres (16 feet) deep, should use a personal fall protection/rescue harness system which will arrest a fall and allow for rescue/recovery if necessary. Such systems are often part of the employer's confined space entry program for work in and around manholes.

A worker assigned to enter manholes should receive training that includes awareness of the limited step depth and width for manhole rungs and the need to proceed cautiously when climbing into or out of a manhole. Training should also include procedures to assess the integrity of the steps or rungs when going into a manhole that has not been entered for a while, as rungs may have deteriorated due to corrosion or become loose due to deterioration of the supporting concrete or other material in the riser or cone sections.

The above acceptance of ASTM Specification C 478M is intended to apply to manholes where entry into such manholes is infrequent; for example, access to manholes is typically in the range of once or twice per year. If more regular access is required, such as monthly or more frequently, ladder access meeting the requirements of ANSI Standard A14.3 American National Standard for ladders-fixed-safety requirements should be provided. It is not the intention of the Board to require existing manholes which are currently used frequently to be modified to accommodate a fixed ladder. However, new facilities where frequent entry is going to be made should be sized and installed with a proper fixed ladder. A ladder in a well or shaft is required to meet the ANSI standard.

G13.2(1)-2 Application of CSA and ANSI standards for suspended stages

Issued December 3, 2007

Regulatory excerpt
Section 13.2(1) of the OHS Regulation ("Regulation") states, in part:

A ladder, window cleaner's belt or work platform must meet and be used in accordance with

(a) the applicable CSA or ANSI standard in effect when the equipment or structure was manufactured, except as otherwise determined by the Board,...

Purpose of guideline
WorkSafeBC has determined that suspended stage work platforms must meet and be used in accordance with specific standards. The purpose of this guideline is to describe the required standards for suspended stage work platforms.

Background information
Suspended stages are movable work platforms that are supported by line(s) from a building or structure, and can be repositioned vertically during use. They include permanent powered platforms, swing stages, and boatswain's (bosun's) chairs. See also OHS Guideline G13.1 - Types of Work Platforms.

There are a number of Canadian Standards Association (CSA) and American National Standards Institute (ANSI) standards that address design, construction, installation, and use of work platforms. See OHS Guideline G13.2 - Standards acceptable to the Board for a list of some of these standards. The listed standards specific to suspended stages are

    CSA Z271 Safety Code for Suspended Elevating Platforms
    CSA Z91-02 Health and Safety Code for Suspended Equipment Operations
    ANSI A120.1 Safety Requirements for Powered Platforms for Building Maintenance
    ANSI A10.8 American National Standard for Construction and Demolition Operations - Scaffolding - Safety Requirements

Each of these standards has multiple editions, and a number of elements of design, construction, and use are addressed in more than one standard. This has resulted in some confusion as to which are the applicable standards.

Determination of applicable standards for design, construction, and installation of suspended stage equipment
WorkSafeBC has determined that suspended stages must meet the design, construction, and installation requirements (and any associated maintenance requirements) of any of the following CSA and ANSI standards in effect when the equipment was manufactured

    CSA Z271
    ANSI A120.1
    ANSI 10.8

The applicable editions of CSA Z271 standards for design, construction, and installation of suspended stages used for gaining access to exterior and interior building surfaces and other structures for the purpose of construction, demolition, or building maintenance are

    A. CSA Z271-98 Safety Code for Suspended Elevating Platforms
    B. CSA Z271-M84 Safety Code for Suspended Powered Platforms
    C. Supplement No.1-1977 to CSA Z271-1974
    D. CSA Z271-1974 Safety Code for Powered Platforms

The applicable editions of ANSI A120.1 standards for design, construction, and installation of powered suspended stages used to gain access to building surfaces for building maintenance are

    A. ANSI/ASME A120.1-2006 Safety Requirements for Powered Platforms and Traveling Ladders and Gantries for Building Maintenance
    B. ANSI/ASME A120.1-2001 Safety Requirements for Powered Platforms for Building Maintenance
    C. ANSI/ASME A120.1-1996 Safety Requirements for Powered Platforms for Building Maintenance - Addenda A - 1997; Addenda B - 11/12/1999
    D. ANSI/ASME A120.1-1992 Safety Requirements for Powered Platforms for Building Maintenance
    E. ANSI/ASME A120.1-1970 Safety Requirements for Powered Platforms for Building Maintenance

The applicable ANSI A10.8 standards for design, construction, and installation of suspended stages used to gain access to building surfaces for construction and demolition operations are

    A. ANSI/ASSE A10.8-2001 American National Standard for Construction and Demolition Operations - Safety Requirements for Scaffolding
    B. ANSI A10.8-1998 American National Standard for construction and demolition operations - scaffolding - safety requirements
    C. ANSI A10.8-1988 American National Standard for construction and demolition operations - scaffolding - safety requirements
    D. ANSI A10.8-1977 American National Standard Requirements for Scaffolding

Determination of applicable standard for the use of suspended stage equipment
WorkSafeBC has determined that the use of a suspended stage must meet the requirements of CSA Z91-02 Health and Safety Code for Suspended Equipment Operations. This is the required standard regardless of the year of manufacture of the equipment. The standard specifies safety requirements for use of equipment normally used for window and general cleaning, painting, maintenance, inspection, construction operations, and similar work. The following elements of use are addressed in CSA Z91-02:

  • Training requirements for operation and occupancy of suspended stages
  • General safety requirements such as weather restrictions, equipment and tool use and storage, signage, overhead protection, and fall protection
  • Equipment operation, including general safety requirements, maintenance, use of suspended lines and lifelines, fall-arrest equipment, anchorage, support systems, work units, acceptable landings, special applications such as working from operable windows, and rigging techniques and practices
  • Periodic inspection and testing of temporary and permanently installed equipment and anchor systems
  • Documentation, such as the equipment log, roof plan, work plan, rigging plan, and fall protection procedures

There are also informative appendices to this standard. Although these are non-mandatory parts of the standard, they provide useful safety information for users of suspended stages. The appendices are entitled Work Plan and Emergency Response Plan and Washing Windows in Complete Safety.

Other acceptable standards
There may be an instance where a person finds it impracticable to comply with the above standards. In this case, application should be made to WorkSafeBC for acceptance of an alternate standard.

Note that Regulation s.2.3 specifies that the provisions of the Regulation prevail if there is any conflict between a prescribed code or standard and the Regulation.

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Guidelines Part 13 Division 2 - Ladders

G13.4 Ladder ratings and selection

Issued January 1, 2005

Section 13.4 of the OHS Regulation states:

A manufactured portable ladder must be marked for the grade of material used to construct the ladder and the use for which the ladder is constructed.

A portable ladder certified or rated as meeting the requirements of the CSA or ANSI standards is classified into one of the following categories:

Intended Use Load Rating Ladder Grade/Type Agency
Construction, utilities, and industrial Heavy duty
1
 CSA
I or IA
 ANSI
Light maintenance, office, and farm Medium duty
2
 CSA
II
 ANSI
Household only Light duty
3
 CSA
III
ANSI

Only CSA Grade 1 or ANSI Ladder Type IA or Type I ladders should be used to support ladder jacks and scaffold planks.

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Guidelines Part 13 Division 3 - Work Platforms

G13.8 General requirements - Chair design

Issued August 1, 1999; Revised January 1, 2005

Section 13.8 of the OHS Regulation states:

Each work platform must

(a) have sufficient strength to bear the load to be placed on it, and

(b) be secured against separation from the supporting equipment, structure or surface to which it is attached.

A boatswain's chair raised and lowered by manually powered hoisting equipment, or used with a "descent only" rigging arrangement, should be designed to support a minimum load of 250 pounds. Generally the chair will have a minimum 3/4 inch thick plywood seat, attached at the four corners by minimum 1/2 inch diameter nylon rope to a master link, or be constructed to provide equivalent strength, and have a lap belt to secure the chair to the worker.

A powered (motorized) boatswain's chair is a powered platform and must meet the requirements of CSA Standard CAN-Z271, Safety Code for Suspended Elevating Platforms under section 13.2(1) of the OHS Regulation.

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Guidelines Part 13 - Division 4 - Scaffolds

G13.14 Guardrails on end frame scaffolds

Issued August 1999; Revised January 1, 2005

Section 13.14(2) of the OHS Regulation states:

Guardrails may be omitted from the edge of a work platform if

(a) the platform is adjacent to a structure that provides protection equivalent to guardrails, and

(b) the open space between the platform and the structure is equal to or less than 30 cm (12 in.)

Standard tubular or other cross-bracing forming an "X" pattern on cross-braced end-frame scaffolding should not be used as an alternative to standard guardrails because it does not provide at least equal protection to a top rail and intermediate rail.

G13.19 When and how to ground metal scaffold

Issued January 1, 2005

Section 13.19 of the OHS Regulation states:

A scaffold must be effectively grounded if

(a) it is a metal scaffold and is located close to a high voltage energized electrical conductor or equipment, and

(b) a hazardous level of electrical charge is likely to be induced in the scaffold.

This guideline describes when a metal scaffold near an energized high-voltage conductor or equipment should be grounded. It also provides guidance to consider grounding when a metal scaffold is near a low voltage but "high energy" system.

When a scaffold is erected parallel to an energized high-voltage electrical conductor or equipment there is a potential hazard of voltage being induced into the scaffold. The actual voltage level induced into the scaffold will be influenced by a number of factors such as:

  • Distance from the conductor or equipment (whether overhead or underground)
  • Length of scaffold parallel to the conductor or equipment
  • Voltage and/or current flow in the conductor or equipment

The scaffold should be grounded immediately in either of the following situations:

  • A worker feels an electric shock at any time, including during the erection of the scaffold.
  • A voltage potential of more than 30 volts is measured between the metal scaffold and a ground point at least 5 metres (15 feet) from the base of the scaffold.

The following example explains how conditions may vary. Consider a metal scaffold system being erected parallel to an energized high-voltage conductor (power line), and about 6 metres (20 feet) away from the line. When the scaffold is about 30 metres (100 feet) long, a potential difference of 29 volts is measured between the scaffold and the chosen ground point. A voltage less than 30 volts is not considered hazardous, so no grounding would be required (unless workers report feeling an electric shock). When the scaffold was extended to 100 metres (300 feet) long, the induced voltage is now measured at 90 volts. Workers touching the scaffold while standing on the ground, or touching part of an adjacent building or structure while on the scaffold, may feel a shock. Although there may not be sufficient power to cause a direct electrical injury, the shock could startle the worker and the worker's reaction could result in a forceful contact with an object or in a fall. In this case the scaffold should be sufficiently grounded before further use.

If metal scaffold is erected adjacent to the main power feed and/or distribution panel for a large building, or adjacent to the supply conductor for a large electric motor, the voltage of the electrical equipment may be below the limit of "high voltage" (750 volts) but due to the high current flow in the electrical equipment, a strong electric field may be present and capable of inducing a voltage in the scaffold. For example, the main power supply to a large building may be operating at 600 volts and carrying 400 amperes of current. Likewise, an electric motor for a large saw or pump in a mill may be operating at 440 volts and drawing 150 amperes of current. These systems are usually isolated by effective cover to eliminate any hazard of direct electrical contact, but metal scaffold elements erected parallel to the electrical equipment may have a voltage induced due to the high electric field present around such electrical equipment. If a worker reports feeling electric shocks upon touching the scaffold, or if a voltage of more than 30 volts is measured between the scaffold and a ground point, the scaffold should be grounded.

Effective grounding

There are different methods of grounding the scaffold so that any induced voltage is immediately dissipated so as not to pose a hazard to workers. The ground-connecting fixture should be connected to the scaffold with a #2 AWG copper conductor. The scaffold should be grounded at both ends. Suitable ground-connecting fixtures are ground plates or rods.

The installation of the grounding should be in accordance with the BC Electrical Code.

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Guidelines Part 13 Division 5 - Movable Work Platforms

G13.23(1) Inspection and certification of elevating work platforms

Issued January 1, 2007

Regulatory excerpt
Section 13.23(1) (Testing) of the OHS Regulation ("Regulation") states:

(1) A vehicle-mounted elevating work platform and a self-propelled boom-supported elevating work platform must be

(a) inspected in accordance with good engineering practice at least every 12 months, and

(b) certified in writing by the equipment manufacturer or a professional engineer as complying with this Part and safe for use.

Purpose of guideline
This guideline outlines 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 and that the equipment complies with the Regulation and is safe for use.

The concept of good engineering practice
The annual inspection and certification of a vehicle-mounted elevating work platform or a self-propelled boom-supported elevating work platform 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 BC, the engineer, as required by the Engineers and Geoscientists Act, must be licensed to practice in BC. If this work is being done outside BC, for example in Alberta, the engineer must be licensed to practice in that jurisdiction.

If certification is to be provided by the equipment manufacturer, the person signing on behalf of the manufacturer must 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 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 and their extent, including dismantling, assessment and NDT or other testing, will be determined by the certifying professional. The factors relevant in making these determinations include:

  1. Requirements of the applicable regulations, safety codes and standards
  2. The equipment manufacturer's specifications and instructions
  3. The certifying professional's familiarity with the particular design and model of equipment, including known reliability problems or component problems
  4. Previous inspection history and results
  5. Age of the equipment and number of hours of use
  6. Circumstances of use of the equipment (for example, heavy duty vs. light use) and any known incidents since the last certification
  7. The general condition of the equipment
  8. The environment in which the equipment has been used (for example, a corrosive environment vs. a clean, dry shop or yard area)
  9. The available use, service, inspection and maintenance records
  10. 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. 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.

G13.25 Warning devices

Issued January 1, 2005

Section 13.25 of the OHS Regulation states:

(1) An elevating work platform, except a vehicle-mounted work platform, must have a warning system consisting of an intermittent horn or flashing light that

(a) is automatically activated during any motion of the work platform, and

(b) can be seen or heard by other workers in proximity to the work platform.

(2) If the safe operation of an elevating work platform requires its carrier vehicle to be on a level surface or level within specified degrees, the platform must be fitted, as the carrier requires, with a device to warn the operator that

(a) the carrier is not level, or

(b) the carrier is outside the permitted degrees from level.

This guideline describes appropriate warning signals to indicate any motion of a work platform and devices to warn when the vehicle is not level.

Section 13.25(1)(a) uses the phrase "any motion of the work platform." This phrase applies to raising and lowering the work platform as well as movement of the support base. The raising or lowering motion may create pinch or shear points in the exposed support mechanisms, or components of the support mechanism or platform may enter work areas occupied by other workers.

The design or selection of an appropriate warning system (intermittent horn or flashing light) to satisfy the requirement of section 13.25(1)(b) will depend on the circumstances of use of the platform.

  • If an audible warning device is selected, an automobile-type horn or a "backup alarm" is generally found to be satisfactory for this purpose, provided it is loud enough to be heard by workers over the ambient noise level in the work area, including any workers wearing hearing protection. An audible warning system may have a volume adjustment to allow the warning signal volume to be raised or lowered to accommodate work site conditions.
  • If a flashing light warning system is selected, a rotating beacon or a strobe-type light, visible for 360 degrees about the machine, is generally found to be satisfactory.

Section 13.25(2) requires a device to warn the operator when the carrier is off level or beyond the tilt limit specified by the manufacturer.

  • One method of complying with this section is to have a "tilt alarm" or other suitable signalling device that activates automatically when the platform is elevated and the carrier is off level beyond the specified tilt limit. Few "finished floor" surfaces are perfectly level but they generally do not have a slope of more than 5 degrees. A carrier vehicle tilted less than 5 degrees is generally considered as level.
  • If a manually read indicator is used, it should allow the operator to determine when the carrier is off level by more than the manufacturer's specified limit or 5 degrees, whichever is less.

Some elevating work platforms are designed so the work platform always has the same tilt as the carrier or base; for example, most scissor lifts would be this type. For such units, a manually read tilt indicator mounted where it can be viewed during operation of the unit's controls may be suitable. A spirit level type arrangement used as a manually read tilt indicator (for example, a bent tube containing liquid or a moving ball or a cat's eye bubble) may be suitable, as long as the device will reliably indicate when the maximum permitted tilt angle is reached or has been exceeded.

G13.29 Lower travel limit devices

Issued May 17, 2006

Regulatory excerpt
Section 13.29 of the OHS Regulation states:

(1) Cranes, winches and other devices used for hoisting and lowering movable work platforms must

(a) be operated as slowly as practicable while supporting the work platform,

(b) be lowered under power, if the device is powered, and

(c) not be equipped with a free running boom or hoisting winch controlled only by brakes.

(2) If a moveable work platform is suspended from a crane, winch or other device over a structure that cannot safely support its weight or if other hazards exist below the platform, lower limit travel devices compatible with the hoist system must be used to ensure the platform cannot be lowered beyond the safe lower limit of travel.

(2.1) If the lower limit travel devices required by subsection (2) are not practicable, the employer must ensure that work procedures acceptable to the Board are used that will minimize the risk of the platform going beyond the safe lower limit of travel.

(3) A trial lift for a work platform suspended from or attached to a crane or hoist must be performed at all work locations before the platform is occupied.

Purpose of guideline
This guideline provides information on the application of section 13.29(2) and (2.1) of the OHS Regulation. In particular, it addresses the issue in subsection (2) of hazards below the platform, and in subsection (2.1) the circumstances in which lower limit travel devices may not be practicable.

Hazards below the platform
The intent of section 13.29(2) is to ensure that lower limit travel devices are used to prevent a work platform, including a permanent or portable powered work platform, or a boatswain's chair, from being lowered beyond a safe level. These devices are needed if the work platform is suspended over a structure that cannot safely support its weight, or if other hazards exist below the platform.

Some examples of the hazards that might exist below a work platform include water that is deep enough to present a hazard of drowning, energized and exposed high voltage equipment, a canopy entrance to a building, the entrance to the underground parking area of a building, or circumstances where the platform is above vehicle traffic or moving machinery.

Practicability of lower travel limit devices
Lower limit travel devices are generally practicable if the hoisting equipment being used is a powered swing stage (permanent or portable powered platform). The CSA Standard Z271 Safety Code for Suspended Elevating Platforms, clauses 7.3.12.4.2 and 8.3.6.4.3, requires such equipment to have lower limit travel devices if there is a hazard in the event of descent beyond a predetermined point. Most permanent powered platforms will have automatic lower limit travel devices. Many portable powered platforms use a cable climbing hoist. For these types of hoists, the use of cable clips positioned at the appropriate spot on the hoist line(s) may be considered a lower limit travel device.

In circumstances where section 13.29(2) and (2.1) apply, the use of a lower limit travel device is the preferred means of worker safety. The use of work procedures will be acceptable only where lower limit travel devices do not exist or are not practicable.

Lower limit travel devices are generally not practicable for work platforms suspended from a crane load line or a winch load line. If a winch or drum hoist is being used, painting a warning mark on the hoist line at an appropriate spot may be part of the work procedures for controlling lower travel limits. The work procedure would need to include the use of a signaler to direct the crane, or a hoist operator where the operator does not have an adequate view of the platform to safely move the platform under the direction of a designated signaler on the platform.

G13.30 Work platforms supported by a lift truck

Issued August 1999; Revised January 1, 2005; Editorial Revision February 6, 2006; Revised February 1, 2008

Regulatory excerpt
Section 13.30 of the OHS Regulation states:

(1) A work platform supported by a lift truck may be used to support people only if other conventional means of access for the task, such as ladders, scaffolds and elevating work platforms, are not practicable

(2) A work platform supported by a lift truck must be designed and used in accordance with WorkSafeBC Standard 13.30 Work Platforms supported by Lift Trucks.

Purpose of guideline
This guideline provides information on the application of WCB Standard A324 to platforms built prior to April 1998.

Platforms built prior to April 1998
WCB Standard A324 was withdrawn April 1998. Any platforms built prior to that date and constructed to meet the standard can continue to be used and maintained to that standard. New platforms must meet WorkSafeBC Standard 13.30 Work Platforms supported by Lift Trucks.

G13.32 Prior permission - Platform use in high risk situations

Issued August 1999; Revised January 1, 2005; Revised February 8, 2007

Regulatory excerpt
Section 13.32 of the OHS Regulation ("Regulation") states:

A swing stage, boatswain's chair and portable powered platform must not be used without prior permission of the Board if

(a) one work platform will be used above or below any portion of another work platform,

(b) a deck or planking will be used to span a gap between two independent work platforms,

(c) the work platform will exceed 10 m (32 ft) in length, or

(d) the suspension height will exceed 91 m (300 ft).

Purpose of guideline
A person who wishes to use a swing stage or portable powered platform in any of the configurations listed in section 13.32 must first get permission from WorkSafeBC. This guideline

  • Outlines the legislative context of section 13.32
  • Provides summary information on how to submit applications under section 13.32, and the issues to address in the submissions
  • Sets out the items that need to be addressed in work procedures and systems for the four different work platform configurations covered by section 13.32. For section 13.32(d) the guideline provides detailed information on the risk factors associated with suspension heights, and outlines matters to consider when assessing the appropriateness of use of different types of work platforms

1. The legislative context of section 13.32
Part 3 of the Workers Compensation Act ("Act") establishes, among other things, responsibilities for safety. Typically, the use of suspended work platforms involves various parties. The employer, worker, and supervisor have responsibilities for safety under sections 115 to 117 of the Act. Owners of buildings have responsibilities under section 119, and suppliers of work platforms and other equipment under section 120. Prime contractors, if involved, have the responsibilities established by section 118.

The effective discharge of these responsibilities should result in an integrated system and plan for worker safety, that begins with consideration of the structure of the building or facility. The plan should also include the development and use of equipment and systems that ensure safety, coupled with instructions on safe use and the training of workers.

In Part 13 of the Regulation, section 13.32 is just one of a number of requirements that address the safety of workers on work platforms. For example, section 13.2 (Standards) requires that work platforms meet and be used in compliance with acceptable standards. OHS Guideline G13.2 Standards Acceptable to the Board lists these standards. The standards for work platforms deal with matters including equipment design, installation, maintenance, inspection and use, as well as worker training.

Two standards of note are the most recent CSA standards

  • Z271-98 Safety Code for Suspended Elevating Platforms
  • Z91-02 Health and Safety Code for Suspended Equipment Operations

The focus of CSA Standard Z271-98 is on equipment design, construction, and installation; and of CSA Standard Z91-02, on usage and training.

The foundation elements for managing safety under CSA Standard Z91-02 include the roof plan, work plan, equipment log, and worker training.

The roof plan, signed and sealed by a professional engineer, is provided by the building owner and covers matters such as essential structural members (including anchors), details of any permanent equipment, safe working loads and use restrictions, and any obstacles that can impede the safe use or operation of equipment. The work plan is provided by the employer for every project where suspended equipment will be used, and covers matters such as the planned work activities and procedures for fall protection and use of equipment, including a rigging plan and emergency procedures.

The CSA Standard Z91-02 also requires the owner of equipment to keep a log for the equipment covering matters such as operating instructions, installation records, and records of inspection and maintenance. Part 3 of the Standard addresses worker training.

Where systems are permanent, plans will typically be consistent from one use to the next. However, where systems are temporary, each usage may require the development of new plans in order to achieve compliance with standards.

Other applicable requirements in Part 13 include section 13.3 (Inspections), and various provisions in the Divisions on Work platforms and Moveable work platforms.

2. Applying for a prior permission under section 13.32
Applications for prior permissions are to be submitted to the Regulatory Practices Department of the Worker and Employer Services Division of WorkSafeBC. Applications need to provide information on responsible parties, the training and experience of workers, the work activity, the equipment involved, and the specific procedures to be used.

In addition, WorkSafeBC may require assurance of compliance with the various applicable provisions of Part 13, if for example, there are indications that compliance may not already have been achieved.

  • Party(ies) responsible for worker safety
    The employers and other parties who will be responsible for the safe use of the platform should be identified. Where it is known that more than one party will use a platform all should be listed in the application.

    If a platform is leased from a supplier, the supplier should also be identified. Suppliers have responsibilities under section 120 of the Act for the provision of safe equipment and instructions on its safe use. Prime contractors and building owners, as applicable, also carry responsibilities under sections 118 and 119 of the Act. Among other things, facility owners have an obligation to maintain the premises in a manner that ensures the health and safety of persons at the workplace, and to provide information that is necessary to identify and control the hazards.

  • Training and experience of workers
    The application should include information on the training of workers, their experience, and on the orientation to be provided at the specific worksite. Part 3 of CSA Standard Z91-02 outlines areas in which workers are expected to be knowledgeable and capable, including: applicable regulations, general safety procedures established by the manufacturer and/or employer, specific procedures for the safe use of the equipment & rigging, and emergency procedures. Workers should also be knowledgeable of the roof plan, including means of anchorage, and of the work plan for the site.

  • Work location and activity
    The application needs to include information on the work location, work activity to be done from the platform, the proposed duration of the work, and where feasible, an estimate of the weather conditions to be expected during the period of work.

  • Equipment to be used, and its integrity
    Technical information is needed about the equipment, and its integrity. The integrity of the system will be assured, in part, by an ongoing program of inspection and maintenance, as documented in the equipment log.

  • Work procedures and systems to be used
    Applications need to include specific information on the procedures and systems used to ensure safety, including emergency procedures, applicable to the configuration of the work platform(s) for which the prior permission is requested. Details of the matters to be addressed for each of the configurations covered by section 13.32(a) - (d) are provided in the remainder of this guideline.

3. Work procedures and systems for the configurations under s. 13.32(a) - (d)
(a) One work platform above or below any portion of another work platform
Information in a submission is expected to address matters including

  • Appropriate head protection when there is a potential of objects falling onto workers on the lower platform(s)
  • A procedure for communication between the workers on the different platforms
  • A system to help ensure that the suspension lines do not become entangled during use
  • A procedure for maintaining safe clearance between the platforms while positioning, lowering, or raising the stages
  • A fall protection system located in an effective position that minimizes the risk of entanglement with other lines
  • Types and locations of hoists. Hoists on the upper platform should be manually operated to minimize the risk of the upper platform landing on the lower one

(b) Bridging between two independent platforms
Information in a submission should include

  • The arrangement and procedure for use as certified by a professional engineer
  • Provision for a qualified operator at the controls of each raising and lowering mechanism when a platform is being moved, to ensure synchronized travel of the suspension points
  • A procedure to ensure allowable distribution of workers and materials on the system so that that the rated capacity of any hoist or platform is never exceeded
  • A method of securing bridging components to the platforms to prevent dislodging and to allow for expected articulation movement between the system components

(c) A work platform longer than 10 metres (32 feet)
Information in a submission should include

  • The load rating and load distribution as specified by the platform manufacturer or certified by a professional engineer
  • Consideration of the additional dead weight of the longer platform compared to a standard platform, and how this has been addressed in choosing or designing the means of platform suspension
  • Confirmation that the hoisting units and suspension system are capable of safely handling the rated load for the system

(d) A work platform at a suspension height of more than 91 metres (300 ft)
The height limitation established by section 13.32(d) is based on the understanding that additional risks affecting worker safety may occur in circumstances where suspension heights exceed 91 m/300 ft (long line situations).

Seven risk factors are discussed below. In addition, a list is provided of procedure and system issues that need to be addressed in a submission. The guideline also discusses the appropriateness of different types of equipment use.

Risk factors in long line situations
The risk factors outlined below are generally present with any suspended work platform, regardless of suspension height. However, they are particularly an issue in long line situations.

(1) Wind loading
Wind velocities, and consequently wind loads, are greater at higher elevations and vary depending on the locale. The effect of wind on a bosun's chair (also termed a boatswain's chair or rope descent system) can present a greater risk than on a swing stage. For additional information, refer to Commentary B in the National Building Code document titled Structural Commentaries (Part 4) - NBC 2006.

Lateral displacement of the suspended platform due to wind can be controlled by using continuous or intermittent tie-ins to the building. A number of requirements are detailed in CSA Standard Z271-98. For a bosun's chair, CSA Standard Z91-02 requires stabilization for suspension heights of more than 46 metres (151 feet). The Standard accepts suction cups for this purpose.

(2) Line elongation
In the event of a fall, lifeline elongation at lower elevations may create a risk of injury to a worker, given that the worker may impact the ground or other surface before deceleration has ended. This can be minimized by selecting a lifeline having low elasticity, coupled with a personal energy absorber to limit the peak arrest force encountered, should a fall occur.

(3) Weights of lines and cords
The additional weight of longer suspension lines and power cords can impose greater loads on the system, and must be included when establishing the working load limit for the platform and ensuring that the rated capacities of the hoists and other suspension components are not exceeded.

In addition, the weight of lifelines, suspension lines and power cords being handled by workers situated at the roof's edge increases with line length.

(4) Line safety at or near ground level
The longer the lines on a system the more difficult it can be to manage line safety at or near ground level. Examples of hazards include power lines and vehicular traffic.

(5) Voltage drop
The length of power cord can result in a voltage drop at the hoist, thereby reducing the power available to meet requirements for the hoist's rated capacity.

(6) Rescue
Rescue may be more difficult in a circumstance with long suspension lines. An effective rescue plan is essential.

(7) For a bosun's chair, the operation of the descender
In addition to the above risk factors, bosun's chairs present an issue of risks associated with the descender. For example, the weight of the suspension line hanging below a descender can adversely affect the operation of the descender over its range of travel.

Also it is recognized that when descenders are used for long drops, friction can lead to substantial heating of the device. If, after a long drop, the device comes to rest at a particular point on the descent line, it may cause heat damage at that location on the line. The device may present a burn hazard to the worker.

Procedures/system issues to be addressed for long line situations
Before applying for an acceptance of a long line configuration under section 13.32(d), the applicant(s) should attempt to develop a strategy for conducting the work that does not involve suspension lengths of more than 91 metres (300 feet). Building design can be a key factor in assessing the options.

If long lines are considered necessary, a submission is required to be made to WorkSafeBC, addressing matters such as

  • The reason(s) why long lines are considered necessary
  • A lanyard for a personal fall protection system designed and used to minimize free fall
  • The use of a shock absorbing device with each lanyard
  • A lifeline for a personal fall protection system with characteristics that minimize elongation of the rope under load
  • A means of managing line safety with respect to hazards at or near ground level
  • A mechanical device to raise, lower, or re-position suspension lines and power supply cables when working at or near the edge of the roof. An alternative acceptable to WorkSafeBC is the use of at least two workers to conduct the procedure, and fall protection measures will need to be in place.
  • A means or procedure to monitor wind speed and a procedure for stopping work when wind speed exceeds 30 km/h (19 mph) at the work platform
  • Wherever practicable, a means of stabilizing suspension lines, and securing the platform to the building face when the platform is in a stationary position
  • A means of restraining lifelines at or near the midpoint if over 100 m (328 ft) long
  • Procedures for rescue in case of equipment malfunction or other emergency

Comments on the use of types of work platforms in long line situations
It has been established industry practice that for drops exceeding 91 m (300 ft), suspended platform installations typically employ four-point suspension. In this scenario the system is designed so that a worker can secure his or her fall protection lanyard to the platform, rather than to an independent lifeline suspended from above. Four-point systems address a number of risk factors in long line situations.

If independent lifelines are used, steps need to be taken to address applicable risk factors as they apply to the lifelines. Note that CSA Standard Z271-98 permits lifeline lengths up to 150 m (492 ft), provided that midpoint restraint is utilized for lengths over 100 m (328 ft).

A bosun's chair presents a number of risks that are unique to chairs or may be of more significance than for other work platforms. Section 13.2 of the Regulation references both CSA and ANSI standards. The CSA Standard Z91-02 prohibits use of bosun's chairs where the suspension height exceeds 300 ft. In addition, the current ANSI (IWCA) Standard I-14.1 Window Cleaning Safety states that descents must not exceed 300 feet unless the windows cannot be safely and practicably accessed by other means.

Due to these concerns, WorkSafeBC will consider prior permissions for bosun's chairs for suspension heights of more than 91 m (300 ft) only where access cannot be achieved safely and practicably by other means, and then, only in circumstances that are marginally (about 10%) beyond 91 m.

Even if a suspension height is only marginally longer, WorkSafeBC may not grant an acceptance if the application does not adequately address the risk factors involved. If the line length proposed is more than marginally beyond 91 m, a prior permission would only be considered in an exceptional circumstance where reasons are compelling and worker safety is assured.

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Disclaimer: The Worker and Employer Services Division issues Guidelines to help with the application and interpretation of sections of the Occupational Health and Safety Regulation and with divisions of the Workers Compensation Act that relate to health and safety. Guidelines are not intended to provide exclusive interpretations but to assist with compliance. WorkSafeBC ("Workers' Compensation Board of B.C.") does not warrant the accuracy or the completeness of the online version of the Guidelines and neither WorkSafeBC nor its board of directors, employees or agents shall be liable to any persons for any loss or damage of any nature, whether arising out of negligence or otherwise, which may be occasioned as a result of the use of the online version of the Guidelines.