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Table of Contents: WCB Standards

WCB Standard: A324 Forklift Mounted Work Platforms

Application of G600 Series of Standards
WCB Standard: G601 Log Loader and Log Yarder Backstops
WCB Standard: G602 Log Loader and Log Yarder Raised Cabs
WCB Standard: G603 Log Loader and Log Yarder Window Guards
WCB Standard: G604 Light-Duty Screen Guards For Off-Highway Equipment
WCB Standard: G605 Mobile Equipment Half-Doors
WCB Standard: G606 Boom Boat Operator Protective Structures
WCB Standard: G607 Medium Duty Screen Guard (Front End Log Loader)
WCB Standard: G608 Mobile Equipment Roof Structures - Heavy Duty
WCB Standard: G609 Mobile Equipment Roof Structures - Light Duty

WCB Standard: LDR 1-2004 Job Built Ladders

WCB Standard OFA 1: Certification of Occupational First Aid Attendants

WCB Standard: PPE 1 - 1997 Leg Protective Devices
WCB Standard: PPE 2 High Visibility Garment - Personal Protective Equipment Standard 2

WorkSafeBC Standard 13.30 Work Platforms supported by Lift Trucks new
WorkSafeBC Standard 14.116 Chimney Hoists new

WCB Standard: WPL 1-2004 Design, Construction and Use of Wood Frame Scaffolds

WCB Standard: WPL 2-2004 Design, Construction and Use of Crane Supported Work Platforms

WCB Standard: WPL 3-2004 Safety Factor and Minimum Breaking Strength for Suspended Work Platforms and Associated Components

Retired Standards

The following WCB standards have been retired:

WCB Standard: A321 Self-Propelled Elevating Work Platforms has been replaced by CSA Standard CAN3-B354.3-M82, Self-Propelled Elevating Work Platforms for Use as "Off-Slab" Unit and CSA Standard CAN3-B354.2-M82, Self-Propelled Elevating Work Platforms for Use on Paved/Slab Surfaces

WCB Standard: A322 Elevating Rolling Scaffolds has been replaced by CSA Standard CAN3-B354.1-M82, Elevating Rolling Work Platforms

WCB Standard: A323 Work Platforms Mounted on Industrial Lift Trucks has been replaced by ANSI Standard ASME B56.1-1993, Safety Standard for Low Lift and High Lift Trucks

WCB Standard: A326 Design, Construction and Use of Suspended Platforms

WCB Standard: PPE 14.1 Leg Protection For Chain Saw Users (Agricultural Operations only)

WCB Standard: A324 Forklift Mounted Work Platforms (See Note)

© Workers' Compensation Board of British Columbia. All rights reserved. No part of this document may be copied, reproduced, or distributed for profit or other commercial enterprise, nor may any part be incorporated into any other publication, without written permission of the Workers' Compensation Board of B.C.

Note:
In general, the forklift mounted work platform shall be made and used according to the requirement of ANSI B 56.1- 1993. However, in an individual situation where the requirement of the ANSI standard cannot be complied with, work platforms made to the requirement of WCB Stanard A324 may be used.

Wcb Standard: A324 Forklift Mounted Work Platforms, June 1989

1. Scope

This standard defines safety requirements for forklift mounted platforms which may be used to elevate personnel. The standard covers the following:

work platforms intended only for personnel and hand tools with an attendant forklift operator,
work platforms intended for personnel and materials
1. with an attendant forklift operator and
2. with controls mounted on the platform without an attendant forklift operator.

Where forklift mounted work platforms are inappropriate for the job being performed, suitable elevating work platforms (scissor lifts, boom lifts, etc.) shall be used.

WCB Standard A324 is included in I.H.&S. Regulation 32.36(2)(f) "or other standards acceptable to the Board."

2. Definitions

2.1
The following definitions apply in this standard:

Free descent means the uncontrolled and unintended descent of the platform.
Rated load means the designed carrying capacity of the work platform.
Stability means a condition of a work platform/forklift combination where the sum of the overturning moments, including the presence of personnel or their equipment, or both, is less than the sum of the moments tending to resist overturning.
Work platform means a work platform that can be mounted on the forks of a lift truck to be elevated to overhead work locations.

3. Carrier Lift Truck Requirements

Forklifts used for elevating personnel shall be designed, fabricated, operated, inspected, tested and maintained in accordance with the following standards:

ANSI B56.1 - 1983 "Safety Standard for Low Lift and High Lift Trucks",
CSA B335.1-1977 - "Low Lift and High Lift Trucks"
ANSI B56.6 - 1987 "Rough Terrain Forklift Trucks",
Other standards acceptable to the Board.

Modifications and adaptations to the forklift which will affect its operation, hydraulic system or structural integrity shall be approved by the forklift manufacturer or a registered Professional Engineer.

Forklifts shall be maintained in accordance with service manual requirements.

Forklifts used for elevating personnel shall have a level indicating device attached to the mast to indicate when the mast is vertical. Restraints must be provided to ensure the mast is maintained within five degrees of the vertical position when personnel are elevated.

Forks must be secured against dislodgment.

Where the elevation of the platform is accomplished by a hydraulic cylinder assembly, the system shall be equipped to prevent free descent of the platform in the event of hydraulic line failure.

4. Responsibilities of Users

4.1
The operator must be trained to operate the forklift and must demonstrate proficient machine operation to his supervisor prior to lifting personnel on a work platform.

4.2
Before lifting the platform:

Ensure that the forklift is on level, stable ground and the area is clear of overhead hazards such as powerlines.
Ensure that the load is centred laterally and is positioned as close to the mast as possible.
Ensure that the mast is vertical.

4.3
Forklifts shall be immobilized against inadvertent movement while the platform is occupied.

4.4
For those platforms requiring an attendant forklift operator, the operator shall remain within 25 feet (7.6 m) of the machine controls on ground level with the machine and platform in his view and in communication with the workers on the platform.

4.5
The machine and platform shall be in good operating and structural condition and be maintained as required by the manufacturer.

4.6
Workers shall not climb the forklift mast.

4.7
Rated loads shall not be exceeded.

4.8
Replacement parts for the platform shall meet or exceed the requirements of the original parts.

4.9
The platform shall not be elevated higher than 30 ft. (9 m).

4.10
Workers shall not be transported on the platform.

4.11
Platform occupants shall not work from locations higher than the platform surface.

4.12
Occupants of work platforms shall wear safety belts secured to suitable and substantial anchor-points except while offloading materials from the platforms.

5. General Platform Requirements

All work platforms shall meet the following requirements.

5.1 Design and Manufacture
5.1.1 Basic Principles
Sound engineering and manufacturing principles shall be applied in the design and manufacture of work platforms considering they will be carrying personnel.

5.1.2 Material Requirements
Load carrying members subjected to tension or reversing stresses shall be of materials that do not become brittle at low temperatures.

Bolts, nuts and other fasteners whose failure would result in the free descent of the work platform must conform to or exceed the requirements of ASTM Standard A325, High-Strength Bolts for Structural Steel Joints. SAE Grade 5, the equivalent or better shall also be acceptable.

Wooden platform components shall be constructed from #2 grade or better; species to be limited to the following groups: - Douglas Fir-Larch; Hem-Fir; Spruce-Pine-Fir or Coast Sitka Spruce only. All lumber shall be graded according to the National Lumber Grades Authority Rules or other approved grading rules. All lumber shall be grade stamped by an approved agency.

5.1.3 Welding Standards
All welding shall conform to the following standards:

CSA Standard W59, Welded Steel Construction, (Metal Arc Welding), or
ANSI/AWS Standard D1.1, Structural Welding Code, or
CSA Standard S244, Welded Aluminum Design and Workmanship (Inert Gas Shielded Arc Process).

5.1.4 General
The work platform shall be secured to the fork carriage to prevent forward, lateral or rotational movement. Self-latching mechanisms are acceptable.

The platform shall have suitable dimensions and/or be mounted such that the forks will support at least 75% of the platform dimension parallel to the fork arms but will not protrude beyond the edge of the platform.

The platform shall be constructed so as not to cause any hazard to its occupant(s).

The dangerous parts of all moving machinery including the shearing hazards created by the movement of the lifting mechanism shall be securely guarded against inadvertent contact by occupants of the platform.

The work platform shall have a slip resistant floor surface.

5.1.5 Guardrails
The platform shall have 42 in (1070 mm) high guardrails, intermediate rails and 4 in (100 mm) high toe boards on all sides or be enclosed to a height of 42 in (1070 mm). Guardrails must be capable of withstanding a horizontal force of 200 lbs. (890 N). Chains are not to be used for guardrails.

Guardrails may be removable or hinged for opening during loading and unloading. They shall be constructed to accomplish proper positioning and so that a secured condition is discernible. Where removable guardrails are installed the toe boards must also be removable.

5.1.6
All work platforms shall have an emergency stop button to enable personnel on the platform to shut off power to the lift truck.

5.1.7
Substantial anchor points shall be provided for securing safety belts.

5.2 Platform Identification

Work platforms must have permanent, legible identification providing the following information:

Name and address of manufacturer
Name of engineer (if engineering certification is required)
Platform weight
Platform rated load (carrying capacity)
Minimum carrier forklift requirements:
- wheel track
- forklift rated capacity
- forklift weight

5.3
Any platform with the working surface greater than 12 inches (300 mm) above the level of the forks shall be certified by a registered Professional Engineer with consideration for the diminished fork lift capacity and system stability. The requirements of Section 6.2 apply.

5.4
Where a work platform is mounted on a forklift with side-shift or reaching capability the combination must be certified by a registered Professional Engineer as to its stability in the least stable configuration. The requirements of Section 6.2 apply.

6. Platform Requirements

6.1
Platforms Carrying Personnel and Handtools Only With an Attendant Forklift Operator

6.1.1 Size
These shall be restricted to maximum dimensions of 4 ft. x 4 ft. (1.2 m x 1.2 m). The platform must be positioned with the shorter axis parallel to the forks.

6.1.2 Capacity
The rated load of the platform shall conform to the manufacturer's instructions, however, in no case shall it exceed 500 lbs. (2.2 kN).

6.1.3 Carrier Forklift Requirements
Minimum carrier forklift requirements shall be as follows:

Forklift weight 3000 Ibs. (13.3 kN) or greater.
At maximum extension the forklift capacity shall be 3000 Ibs. (13.3 kN) or greater at 24 in. (0.6 m) load centre.
Forklift wheel track 3 ft. (0.9 m) or greater.

6.1.4
All work platforms shall be structurally sound. Damaged or deteriorated platforms shall not be used.

6.1.5
No modifications shall be made to the work platform without the approval of the manufacturer.

6.2 Platforms Carrying Personnel and Materials
Work platforms intended for carrying personnel and materials or those with a capacity or size greater than allowed for in Subsection 6.1 shall be certified by a registered Professional Engineer and meet the following requirements:

6.2.1 Stability Requirements

Level Surface Stability Requirements

The work platform/forklift combination shall maintain stability while supporting a minimum static load of two times the platform rated load in any working position on a level surface. The centre of gravity of the load shall be within 12 inches (300 mm) of the platform edge with the unit in the least stable configuration.
Horizontal Stability Requirements

When carrying the platform rated load and raised to the maximum working height of the platform on a level surface, the work platform/forklift combination must be stable while sustaining a horizontal force equal to 150 pounds (670 Newtons) or 15% of the rated load, whichever is greater. This horizontal force shall be applied to the perimeter of the platform at the working surface elevation so as to create the most adverse loading condition while the unit is in its least stable configuration. The centre of gravity of the vertical load shall be within 12 inches (300 mm) of the platform edge with the unit in the least stable loading condition.
Five Degree Slope Stability Requirements

The work platform/forklift combination shall be able to maintain stability, while sustaining a static load of 1-1/3 times the rated load of the platform, in every position in which the load can be placed, with the forklift on a slope of five degrees downward in the direction most likely to cause overturning. The centre of gravity of the load shall be within 12 inches (300 mm) of the platform perimeter.

6.2.2 Structural Factors of Safety
All load supporting elements shall be designed with a safety factor of not less than:

2 based on the yield strength for grades of steels or other materials having a minimum elongation at failure of 14% in a gauge length of 50 mm when tested in accordance with ASTM Standard E8, Tension Testing of Metallic Materials; or
5 based on the ultimate strength for cast irons, fibreglass reinforced plastics, or other materials having an elongation at failure of less than 14% in a gauge length of 50 mm when tested in accordance with ASTM Standard E8.

The design stress used in determining the structural safety factor shall be the maximum stress induced in the element with the device operating with its rated load.

6.2.3
Work platforms that have sustained damage such that the structural integrity is suspect shall be recertified by a registered Professional Engineer prior to use.

6.2.4
No modifications shall be made to a work platform without the approval of a registered Professional Engineer.

6.2.5
Control Requirements for Platforms Without an Attendant Forklift Operator

Work platforms may be used without an attendant forklift operator. These shall have both remote hoist and tilt controls mounted on the work platform. An operator is not required to attend the machine controls if the platform controls have been selected for use.

When the platform mounted hoist and tilt controls are in use, means shall be provided to render the hoist and tilt controls on the truck in- operative. Only one set of controls shall be capable of being operated at one time. Only trained operators shall operate the controls on the platform.

An emergency lowering system available at ground level shall be provided. This device shall be protected against inadvertent application, and shall be clearly marked.

Application of G600 Series of Standards

Excavator

Used for road building in woods, in timber (may include residential lot clearing) or
Used for rock scaling

Used for demolition if procedure or conditions are such that a hazard exists.

Crawler Tractor

Cab ROPS

With winch on back

Back opening G604 or SAE J1084

As bulldozer, in woods operations, as skidder

Feller Buncher

Stroke Delimber

Front Window G603 and G604

Styre Delimber

On flat landings or road side logging and decks are at 90° to machine

Front Window G604 or SAE J1084

Roadside logging if log decks are facing the machine

Front Window G603 and G604

Mobile Spar

Cable Log Loader and Grapple Yarder

Forwarder

Skidder

Hydraulic Log Loader on Tracks or Wheels and Butt-N-Top Loader

Operating on a non-cable show with no hazard from sliding logs, no steep terrain

Front Window G603

Operating on a cable show or steep terrain

Rubber Tired Front End Loader

Cab ROPS

One machine in mill yard or two machines moving blocks

Front Window G607

Two machines in mill yard moving tree length logs***

Loading in woods (non cable show) by itself

Front Window G603

Loading at a cable show or working in proximity of other loaders

Boom Boats

Used primarily for towing

Rear Opening G606

*** Unless physical barriers are in place and written work procedure is available and followed to ensure machines do not operate in proximity to each other.

NOTES

Cab Skins

Cab skins must be capable of supporting the window guarding and are to have a strength of not less than the minimum strength required for the guard protecting window openings.

Emergency Escapes

Must be openable from inside and outside.
An escape hatch which leads into an engine compartment is not acceptable unless the escape route is shielded from fire.
Recommended minimum opening

Round (diameter)	650 mm (25.6 in)
Square	600 x 600 mm (23.6 in)
Rectangular	470 x 650 mm (18.5 x 25.6 in)

G603 Guard

A minimum of four inches, and
A maximum of eight inches from the window unless the guard extends sufficiently beyond the side of the window to prevent material from entering the slot posing a hazard to the operator.
Half inch Polycarbonate (Tuffac, Lexan) with suitable substantial supports has been accepted as G603 guarding, i.e., new models of Koehring Feller Buncher and But-N-Top loaders. Such designs must be proven by test or certified design. Written acceptance from the Engineering Section would be based on proof of performance, design and other pertinent factors.

G604

Polycarbonate (Tuffac, Lexan) may be used as an alternative, provided the polycarbonate is:

not drilled
overlaps the cab skin by one inch all around
is mounted on a cab skin which is capable of supporting 4,000 lbs.
is at least 1/4 inch thick if no dimensions of the opening is greater than 40 inches
is at least 3/8 inch thick if any dimension of the opening is greater than 40 inches.

If the polycarbonate material is mounted in another manner it must meet SAE Standard J1084 or other equivalent standard. SAE J1084 is equivalent to or better than G604.

WCB Standard: G601 Log Loader and Log Yarder Backstops, March 1990

1. General

1.1. Scope
This standard pertains to equipment such as log loaders and log yarders and other mobile or stationary equipment where the operator may be exposed to head-on collision or impact with large logs. Examples of mobile equipment where backstops are mandatory are: straight heel boom loaders, crane boom loaders, knuckle boom loaders, dipper stick boom loaders, goose neck boom loaders, Bohemian type boom loaders and grapple yarders. Refer to Standard G602 if the machine does not come within the above category.

1.2. Other References
This standard is supplemented by the following:

1.2.1 G602 W.C.B. Standard for Log Loader and Log Yarder Raised Cabs

1.2.2 G603 W.C.B. Standard for Log Loader and Log Yarder Operator's Cab Window Guards

1.3. Purpose
This standard is intended to describe the minimum requirements for the design and fabrication of grid elements, framework and supports for guards over exposed fronts and sides of operators' cabs.

1.4. Terminology and Illustration

1.4.1 For the purpose of this standard, the following definitions shall apply:

"Backstop" means any protective structure designed to protect the operator from large intruding objects without causing excessive visual interference to the operator. A Backstop may be an integral part of the overall Equipment Protective Structure.
"Equipment Protective Structure" means any protective structure designed to protect the machine from serious impact damage from extraneous objects. It is fabricated with such structural elements as angles, I-beams, Hollow Structural Sections, etc.
"Framework" means the main structural members of a Backstop, consisting of horizontal edge beams, vertical edge beams, and overhead beams. See Appendix "A".
"Main Frame" refers to the structural part of the undercarriage.
"Major Grid Element" means the member along the longitudinal direction of a rectangular frame. Usually, it is the vertical member.
"Overhead Beam" means the member along the lateral direction of a rectangular frame. Usually, it is the horizontal member.
"Substructure" refers to the structural members of the Equipment Protective Structure. The framework may be connected to the Substructure providing that such is capable of transferring the applied load to the Main Frame.
"Supports" refer to the structural members connecting the Backstop onto the Main Frame.

1.4.2 Illustrations attached are shown to clarify the terminology used and are not to be construed as model designs

2. Design Principles and Assumptions

The following points are outlined to clarify the underlying principles and assumptions of this Standard.

2.1.
A static force resistance design criteria is adopted for this Standard.

2.2.
The recommended design force will not necessarily duplicate the force imparted by an actual intruding log.

2.3.
It is assumed that if the Backstop can resist a certain static force, then it will have adequate resistance to a relative dynamic force.

2.4.
A recommended impact strength requirement is included to ensure that all component members of the Backstop will have adequate resistance to brittle fracture at low ambient temperature.

2.5.
A visibility requirement is stipulated to ensure that the operator's vision will not be unduly obstructed.

2.6.
Compliance with the design criteria may be achieved by adhering to the design requirements given in Clauses 3.1.1 and 3.1.2 or by adhering to the recommended minimum sizes in Clause 4.

3. Design Requirements

3.1. Static Strength Requirements
3.1.1 Grid Element
Grid element dimensions and fabrication shall be designed to withstand a minimum distributed area ultimate load of 120 kPa (2500 psf) applied over an area of 0.65 m² (7.0 ft²), equivalent to a 0.92 m (3 ft.) diameter circular area. For design purposes, the distributed load may be applied at each grid junction. (See Appendix "B".)

3.1.2. Framework
The framework shall consist of sections with the following sections modulus:

S > 186 x	L f	metric

S > 4200 x	L f	imperial

S = Section modulus cm³, (in³)
L = Unsupported length of beam cm, (in)
f = Allowable working stress MPa, (lb/in²)

The section modulus (S) shall in no case be less than 50 cm³ (3 in³).

3.1.3 Supports
The Framework shall be secured to the Main Frame or other substructure. Such substructure shall be adequately designed and constructed to resist all loads imposed on them by the Backstop.

3.1.4 Fastenings
If nuts and bolts are used in the fabrication of the Backstop, they shall conform to or exceed the ASTM Designation A325 requirements.

3.1.5 Weldment
Weldments shall conform to applicable sections of General Specification for welding of Steel Structures CSA W59.1-1970 (or latest version thereof) and should be performed by certified welders only.

3.2. Impact Strength Requirement
All members of the guard shall be fabricated of material with good impact absorbing properties. The following guideline may be used:

Low Carbon content (less than 0.28 %).
High Manganese - carbon ratio.
Low phosphorous content.
Fine grain size.
Heat Treated.
High ultimate energy resistance.

Examples of steel meeting or exceeding the above requirements:

ASTM A36, CSA G40.21 33G, 44W - for plates, bars and angles.
CSA G40.21 50W - for HSS

3.3. Visibility Requirements
Minimum interference with operator's visibility shall be one of the governing criteria in the design and positioning of the vertical members of the guard. If flat bars are used as grid elements, they should be in a radiating pattern in line with the operator's line of sight. Each grid opening shall not be greater than 400 cm² (64 in²).

3.4. Location
Backstops shall be installed in front of all sides exposed to collisions with run away or sliding logs. All Backstops shall be positioned at least 10 cm (4 in) (20 cm (8 in) for wire rope Backstops) away from the glazed windows and exterior faces of the cab.

4. Structural Details Guidelines
The following recommendation may be used in lieu of Clause 3.1.1 and Clause 3.1.2.

4.1.
Minimum Minor Grid Element size shall be 1 inch diameter mild steel rods or equivalent.

4.2.
Minimum Major Grid Element size shall be 1/2 x 4 inch bars or equivalent.

4.3.
Minimum edge beam size shall be:

4.3.1	4 x 3 x .2500 HSS for edge beam less than 3'.
4.3.2	6 x 4 x .2500 HSS for edge beam less than 6'.
4.3.3	7 x 5 x .2500 HSS for edge beam less than 9'.

4.4.
Gusset plates shall be incorporated where the length of the edge beam exceeds three feet.

5. Design Aid

5.1. Equivalent Strength Table

	Grid Element
1" diameter mild steel rod	5/8" 6 x 19 IWRC Wire Rope*
1/2 x 4 steel flat bar	3/4" 6 x 19 IWRC Wire Rope*

5.2. Typical Design

Overall Dimension 50" x 98" (See Appendix "B")

X-Section Size

Grid Element
Short direction	1" diameter ASTM A36 rod	5/8" 6 x 19 IWRC Wire Rope*
Long direction	1/2 x 4 ASTM A36 flat bar	3/4" 6 x 19 IWRC Wire Rope*
Edge Beam
Short direction	7 x 5 x .2500 HSS	7 x 5 x .2500 HSS
Long direction	CSA G40.21 (40.16 and 40.17)	CSA G40.21 (40.16 and 40.17)

* Wire Rope may be considered as equivalent provided they are adequately anchored and tensioned. (See illustration attached.)

Materials with equal or superior properties may be use in place of those stipulated in this standard.

G601A Backstop Illustration

G601 Backstops (Typical)

G 601 APPENDIX C.

W.C.B. Recommended Practice for Boom Mounted Backstops

1. Introduction

1.1. Background
OPS Mounting problems have been frequently encountered in retrofitting older log loaders. The lack of sound substructure makes it very difficult to anchor or fasten the OPS adequately. Quite often, the main frame consists only of the turntable bearing mounts. The existing cab substructure is usually too light to permit any significant load transfer to the main frame. The recommended practice which follows summarizes methods to comply with G601 when conventional mounting methods are not feasible.

1.2. Scope and Limits
This recommended practice is directed mainly at track or rubber wheel mounted long crane boom log decking grapple loader engaged in operations such as dewatering where there is a limited hazard from intrusion of debris, logs or other foreign objects into the raised cab from the sides and rear.

Side and rear guards are mandatory whenever the loader or yarder is operating at dry land sorting areas, landings or in proximity to other yarders, standing trees, rock bluffs, etc.

The recommendations herein are not applicable to loaders or yarders equipped with a short boom, i.e. where normal operating radius would be less than 12 M (40 feet) or where the boom angle has to be changed constantly.

1.3. Purpose
This recommended practice is intended to describe the minimum requirements for the design and fabrication of grid elements, framework and supports for guards over exposed fronts of operators cab when all of the above-mentioned conditions have been considered.

1.4. General
The following recommended methods and materials are inferior to those of G601 Appendix A and B. Every effort should be made to comply with G601 Appendix A and B. Appendix C should be used only as a last resort. The backstop may be welded to the crane boom, however such weldment shall be performed by certified welders only and the crane boom shall be recertified by a registered professional engineer whether any actual modifications have been made to the crane boom or not.

2. Design Requirement

2.1. Static Strength Requirements
2.1.1 Grid Element
Grid element dimensions and fabrication shall be designed to withstand a minimum distributed area ultimate load of 1.2 MPa (2500 psf) applied over an area of 0.65 sq.m. (7.0 sq.ft.), equivalent to a 0.92 m. (3 ft.) diameter circular area. For design purposes, the distributed load may be applied at each grid junction.

2.1.2 Framework
The Framework shall consist of sections with the following section modulus:

S > 130 x	L f	metric units

S > 3000 x	L f	imperial units

S = Section modulus (cm³), (in³)
L = Unsupported length of beam (cm), (in)
f = Allowable working stress (MPa), (lb/in²)

2.1.3 Supports
The Framework may be welded or connected by lug and pin to the crane boom. Such crane boom shall be checked and recertified by a registered professional engineer or other person acceptable to the Board.

2.1.4 Fastening
As per 3.1.4 of G601

2.1.5 Weldment
As per 3.1.5 of G601

2.1.6 Braces
Strut braces should be installed at the top and bottom as well as at the middle of the frame.

2.2. Impact strength requirement
As per 3.2 of G601

2.3. Visibility requirement
As per 3.3 of G601

2.4. Location
Refer to 3.4 of G601. In dewatering operations, frontal backstop shall be mandatory. Side guards are optional.

2.5. Dimensions
At normal operating boom angle, the backstop shall extend at least six inches beyond the projected perimeter of the cab. The normal operating boom angle herein is defined as 50° to the horizontal.

3. Structural Detail Guidelines

Materials of better or equivalent properties and strength may be used in lieu of the following:

3.1.
Minimum Minor Grid Element Size shall be 1 inch diameter mild steel rods or 5/8"-6 x 19 IWRC Wire Rope adequately anchored and tensioned.

3.2.
Minimum Major Grid Element Size shall be 1/2 x 4 inch bars or 3/4" - 6 x 19 IWRC Wire Rope adequately anchored and tensioned.

3.3.
Minimum horizontal edge beam size shall be:

3.3.1	4 x 2 x 0.3125 HSS for width up to 3'.
3.3.2	5 x 2 x 0.3125 HSS for width up to 4'.
3.3.3	5 x 3 x 0.3125 HSS for width up to 6'.

3.4.
Minimum vertical edge beam size shall be equal to or greater than the horizontal edge beam size.

3.5.
Gusset Plates shall be incorporated at corners when the length of the edge beam exceeds three feet.

3.6.
Minimum horizontal strut brace size should be 13 x 3 x 1/4.

G601C 1 of 2 Backstop Boom Mounted Illustration

G601C C 2 of 2 for illustration purpose

WCB Standard: G602 Log Loader and Log Yarder Raised Cabs, March 1990

1. General

1.1. Scope

This standard pertains to log loaders and log yarders, and other mobile equipment where the operator may be exposed to hazard caused by intruding or flying objects, such as whipping cables, loose debris, snags, tree trunks, limbs, etc. It is supplementary to G601 Standard for Log Loader and Log Yarder Backstops, and is supplemented by G603 Standard for Log Loader and Log Yarder Window Guards.

1.2. Purpose
This standard is intended to describe the minimum requirements for the design and selection of plates, framework and supports for raised cabs on equipment without a backstop. This will form and provide a protective structure for the operator inside the cab.

2. Design Principles and Assumptions

The following points are stated to clarify the underlying principles and assumptions of this Standard.

2.1.
A static force resistance design criteria is stipulated to ensure that intruding or flying objects will not deflect the cab beyond a certain limit.

2.2.
Also included is an energy design criterion, since in an actual situation involving flying objects, loading will be dynamic and possibly impact. Hence the adequacy of the structure is related more to energy absorption capability and details of weld design and welding procedure rather than static strength.

2.3.
The recommended design horizontal and vertical force will not necessarily duplicate the force imparted by an actual flying object such as trees, whipping cables, etc.

2.4.
As the cab elevation is increased, the vertical load requirement § 3.1.1 may be reduced accordingly.

2.5.
It is assumed that if the cab/structure can resist a force of W (Appendix A), then it will have adequate resistance to whipping cables. A magnification factor has been incorporated into the formulae to compensate for very small logs, because in such cases, other factors such as flying debris or cables may govern. In any case, W used for design purposes should not be less than 9000 N (2000 lb).

2.6.
Although cabs meeting these criteria may not deflect within the Deflection Limiting Volume (DLV See SAE J397a) under all circumstances, it is a minimum requirement for the Cab Protective Structure to have a "Crush Protection" design capability to withstand the force exerted on it by a hypothetical blunt log striking end-on at a velocity of 11 km/hr.

2.7.
Furthermore, there is an impact or strength requirement which is intended to ensure that all members of the cab will have adequate resistance to brittle fracture under cold temperatures.

2.8.
Finally, there is a visibility requirement which is to ensure that the operator's vision will not be seriously obstructed.

2.9.
The operator protective structure can be an integral part of a cab or can be a "cage" outside an existing cab. Hereinafter the term "Cab Protective Structure" shall mean any guard that envelopes the cab or any guard that forms part of a cab. (See Appendix D.)

3. Design Loads

3.1. Vertical Load Requirement

Force Resistance	Fv = 2.5 x Wxi H	units N, m

	Fv = 8.25 x Wxi H	units lb, ft

H = distance from grade to top of Cab Protective Structure.

W = weight of log handled as defined in Appendix A.

Fv = vertical equivalent static force.

i = impact factor as defined in Appendix B or other acceptable method.

Energy Absorption	Ev = 0.152 W	units N, J
Energy Absorption	Ev = 6W	units lb, lb-in

Ev = ultimate energy to be absorbed by the frame at the point of impact. (J), (lb-in).

3.2. Lateral Load Requirement

Lateral Load Requirements

F_L = equivalent lateral static force, where F_L is greater than the tipping force, then F_L may be reduced to that of the tipping force.

4. Design Requirements

4.1. Frame
4.1.1
All frame members of the Cab Protective Structure shall be designed to resist the applied load in accordance with Appendix C or with some other acceptable design criteria to the Board.

4.1.2
In addition, the frame shall be designed to absorb the impact energy as given by Ev and E_L of § 3.1.1 to § 3.1.2.

4.2. Cab Skin
All exposed unguarded sides of the cab should be protected with metal plates

or other suitable material. They shall be designed to resist the F_L as defined in § 3.1.2.

4.3. Supports
The cab protective structure shall be secured to the structural parts of the (carrier) main frame of the log loader or log yarder. Such structural parts shall be adequately reinforced if necessary to resist the loads imposed on them by the cab protective structure.

4.4. Fastenings
If bolts and nuts are used in the fabrication of the guard, they shall conform to or exceed the ASTM Designation A325 Requirements.

4.5. Visibility Requirements
The cab shall be equipped with adequate view areas. All such view areas shall be guarded in accordance with W.C.B. G603 Standard for Log Loader and Log Yarder Window Guards.

4.6. Impact Strength Requirement
All members of the guard shall be made of material with good impact absorbing properties. The following guideline may be used:

Low carbon content (less than 0.28%).
High ratio of manganese to carbon.
Low phosphorous content.
Fine grain size.
Heat treated.
High ultimate energy resistance.

Examples of steel meeting or exceeding the above requirements:

ASTM A36, CSA G40.21 33G, 44W - for plates, bars and angles.
CSA G40.21 50W - for HSS. (Hollow Structural Sections)

4.7. Weldment
Weldments shall conform to applicable sections of General Specification for Welding of Steel Structures, CSA W59.1-1970 (or latest revision thereof) and shall be performed by licensed welders only.

4.8. Alternate Exit
The operator protective structure shall be provided with an alternate exit. Such exit shall have a minimum clear opening of 60 cm diameter (24").

4.9. Glazing
Only safety glass or other suitable material with similar shatter-resistant characteristics shall be used for window areas.

4.10. Sound Isolation and Absorption
The cab interior shall have a sound level reading of not more than 80 db under normal working conditions and with all openings closed. Flammable sound absorption material should be avoided.

APPENDIX "A"

Derivation of W.

The symbol "W" represents weight of the heaviest log expected to be handled by the log yarder or loader. For the purpose or this standard, g (density of logs) should be assigned a value of 560 kg/m3 (35 pcf) which is the arithmetic mean of the common species found in B.C. The following formula may be used to compute the expected weight of incoming logs:

D_B = butt end diameter m, ft.

D_T = top end diameter m, ft.

L = average length of logs handled, m, ft.

g = density of logs handled kg/m³, pcf.

APPENDIX "B"

Impact Factor* (i)

Formula for Impact Factor* (i)

v = velocity of approaching log.

Δ_ST = static deflection of guard member due to weight of approaching log.

g = acceleration due to gravity (32 ft/sec² or 9.8m/sec²).

* Other acceptable method may be used.

Diagram of Loading Conditions for Cab Frame Design (WCB-G602)

Diagram G602 Reinforced Cab and Window Guard (Typical)

WCB Standard: G603 Log Loader and Log Yarder Window Guards, March 1990

1. General

1.1. Scope
This standard pertains to log loaders and log yarders, and other mobile equipment where the operator is exposed to the hazard of intruding or flying objects, such as snapped or whipping cables, loose debris and tree limbs. It is supplementary to other W.C.B. Standards for operator's guards:

The scope and guidelines of each of the above standards shall be correctly interpreted and proper judgement made in determining their appropriate application.

For front end log loaders which are used exclusively in dry land sorting areas, refer to:

W.C.B. - G607 Standard for Medium Duty Screen Guard (Front End Log Loader)

1.2. Purpose
This standard is intended to describe the minimum requirements for the design and selection of rod-size, framework and supports for guards over window areas of operator's cabs. It may also be applicable to other openings such as doorways in certain circumstances.

2. Design Requirement

2.1. Strength Requirements
2.1.1 Grid Element
Grid element sizes and construction shall be designed to withstand a minimum concentrated point load of 666 lbs., (2,963N) working load being applied at each of the four corners of any grid opening, with the critical stresses calculated as a function of the dimensions of the guard.

2.1.2 Edge-beams (Perimeter Frame)
The outer frame shall consist of sections with the following section modulus:

S > 14.9 x	W	Metric Units	For the horizontal edge beam.
S > 14.9 x	f
S > 333 x	W	Imperial Units
	f

S > 14.9 x	L	Metric Units	For the vertical edge beam.
	f
S > 333 x	L	Imperial Units
	f

S = edge beam section modulus, (in³, cm³)

W = width of guard (in, cm)

L = length of guard (in, cm)

f = allowable working stress (MPa, lb/in²)

2.1.3 Supports
The perimeter frame shall be secured to the structural parts of the cab. Such structural parts shall be adequately designed and constructed to resist all loads imposed on them by the Guard.

2.1.4 Fastenings
If bolts and nuts are used in the fabrication of the guard, they shall conform to or exceed the ASTM Designation A325 requirements, or conform to SAE Standard J429 and J995 grade designation 5 through 8.

2.2. Impact Strength Requirement
All members of the guard shall be made of material with good impact absorbing properties. The following guideline may be used:

Low carbon content (less than 0.28%)
High ratio of manganese to carbon
Low phosphorus content
Fine grain size
Heat treated
High ultimate energy resistance

Examples of steel meeting or exceeding the above requirements:

ASTM A36, CSA G40.21 33G, 44W - for plates, bars and angles CSA G40.21 50 W - for HSS

2.3. Visibility Requirements
Minimum interference with operator's visibility shall be one of the governing criteria in the design and positioning of the vertical members of the guard. If flat bars are used as grid elements, they should be in a radiating pattern in line with the operator's line of sight. Each grid opening shall not be greater than 64 square inches (413 cm²).

2.4. Location
Guards shall be installed in front of all window areas exposed to flying or intruding hazards. All guards shall be positioned at least 4 inches (10 cm) and not more than 8 inches away from the glazed windows or exterior faces of the cab.

3. Structural Details

3.1.
Minimum grid element size shall be 3/4 inches diameter steel rods or equivalent.

3.2.
Grid element rod sizes shall be proportionately increased as the dimension of the guard increases.

3.3.
Gusset plates shall be incorporated where the length of the edge beam exceeds three feet.

3.4.
Minimum edge beam size shall be determined in accordance with 2.1.2 but shall in no cases be less than 2 1/2 inch x 1 1/2 inch x 0.125 inch HSS.

3.5.
Materials with equal or better properties may be used in place of those stipulated in this Standard.

4. Design Aid

4.1. Equivalent Strength Table

Grid Element
3/4" dia. Mild Steel Rod	7/16" 6 x 19 IWRC Wire Rope*
7/8" dia. Mild Steel Rod	1/2" 6 x 19 IWRC Wire Rope*
1" dia. Mild Steel Rod	5/8" 6 x 19 IWRC Wire Rope*

4.2. Typical Design
Overall Dimension: 44" x 44"

	Conventional	Alternate
Grid Element
X-Section Size:	3/4" dia. Mild Steel Rod	7/16" 6 x 19 IWRC Wire Rope
Edge Beam	3 x 3 x 5/16 Angles ASTM A36 or CSA G40.21-33G	2 x 2 x .125 HSS (50 ksi yield) CSA G40.21 (40.16 and 40.17)

* Wire Rope may be considered as equivalent provided they are adequately anchored and tensioned. (See illustration attached).

G603 Illustration of Typical Design

WCB Standard: G604 Light-Duty Screen Guards For Off-Highway Equipment, March 1990

1. General

1.1. Scope
This standard pertains to equipment such as tractors, loaders, skidders, where screen type guards are required to protect operators against flying or intruding objects. The guards are intended to resist the penetration by flying or intruding objects or materials into the critical zone which is defined as the Deflection Limiting Volume (DLV) in the SAE Recommended Practice J397a for off-highway equipment.

1.2. Purpose
This standard is intended to describe requirements for the design of supports and framework, and selection of screen material pertaining to light-duty screen guards.

1.3. Terminology and Illustrations *

1.3.1
For the purpose of this standard, the following definitions shall apply:

"Equipment" includes tractors, loaders, skidders and other types of off-highway equipment where operator protection in the form of light-duty screen guards is both necessary and practical.
"Framework" means the frame consisting of the edge stiffeners and intermediate stiffener(s).
"Screen Guard" consists of screens, stiffeners, and all supporting brackets necessary to secure the Guard to its supports.
"Stiffener" refers to any structural member adding rigidity to the screen. It also serves to transfer loads applied to the screen onto the supports.
"Supports" refer to the structural members supporting the Screen Guard, and are usually part of the ROPS (Rollover Protective Structure).

1.3.2
The illustrations are to clarify the terminology used and not to be construed as model designs.

Please see Illustration 5.

2. Location of Screen Guards

2.1.
Back screen guard shall be provided in the area behind the operator.

2.2.
Side screen guard shall extend forward from the back screen guard to at least the forward edge of the operator's seat and shall extend vertically to at least the full height of operator's control area (ROPS or canopy). The screen should not obstruct or restrict the operator's egress from his control area.

2.3.
Front screen guard, where necessary and applicable, shall be provided in front of the operator's control area.

3. Design and Fabrication Requirements

3.1. Design and Fabrication Requirements for Supports
3.1.1
The supports shall be adequately designed and fabricated to resist all loads that the screen guards would likely impose upon them.

3.1.2
On mobile equipment equipped with a rollover protective structure (ROPS), the Screen Guards may be attached to parts of the ROPS, provided that such attachment does not adversely affect the performance of the ROPS. All such attachments shall be clamped unless welding is permitted by the ROPS manufacturer or a Registered Professional Engineer.

3.2. Design and Fabrication Requirements for Screen Guards

3.2.1
The Screen Guard shall resist the penetration by flying or intruding objects or material into the Deflection Limiting Volume as defined by the SAE Recommended Practice J397a.

3.2.2
The screen mesh material should have sufficient flexibility so that the applied load could be distributed over its entire area. Woven, welded wire mesh or other materials of equivalent or better strength properties are acceptable.

3.2.3
The screen mesh shall be fabricated of steel wire material of 6.35 mm (1/4") diameter minimum, having a maximum clear mesh opening of 4.44 cm x 4.44 cm (1 3/4 inch x 1 3/4 inch) square. Such mesh shall be welded to the Framework and should not be welded directly to any ROPS.

3.2.4
The spacing of the edge and intermediate stiffeners should be designed in accordance with the attached "Stiffener Chart."

3.2.5
All free edges of a screen shall be reinforced with stiffeners having a minimum width of 2.5 cm (1 inch) and with the following section modulus:

Section Modulus

Where S = applicable section modulus which shall not be less than .82 cm³ or (.05 in³), based on
fy = 36 ksi, 250 Mpa
L = unsupported length (in) or (cm)

3.2.6
All intermediate stiffeners, where used, shall have a section modulus as recommended in 3.2.5.

3.3. Minimum Design Criteria
The following design criteria may be used in lieu of the recommended sizes and dimensions:

3.3.1
Any area of the screen shall be designed to resist a 18,000N (4,000 lb) static force applied over an area of 62 cm², (9.6 in²).

3.3.2
The screen deflection shall not exceed the limits set by Deflection Limiting Volume per SAE Recommended Practice J397a.

4. Impact Strength Requirements

All components of the Screen Guard and Supports shall be made of material with good impact absorbing characteristic which is assisted by:

Low carbon content (less than 0.28%)
High ratio of manganese to carbon
Low phosphorus content
Fine grain size
Heat treatment
High ultimate energy resistance

Examples of steel meeting or exceeding the above requirements:

ASTM A36, A500, A501, A618, CSA G40.21 Grade 33G, 42W, 50W, 55W

Attachments:

Chart
Sample Designs
Illustrations

Stiffener Chart

APPENDIX G604 SAMPLE DESIGN

Example: To guard a 32" x 48" area against flying or intruding object.
Screen Material Selection
Choose 1/4" x 2" woven steel wire, (1 3/4 x 1 3/4 clear openings)
Framework Design

1. Spacing of Stiffeners (See Stiffener Chart)
Since 48" is the longer dimension, project horizontally along Lu = 48" until the line intersects with 1/4" x 2" woven mesh curve. Project down and read corresponding Wu which is 19".

G604 Sample Design

Alternate Design
Lu = 32
From Chart Wu = 20 < 24 that is required. Not OK.
Increase wire mesh size to 1 ga.
Wu = 38" > 24" OK.

2. Selecting Edge and Intermediate Stiffener Size (3.2.4)

a. Horizontal Edge Stiffener (members No. 1, 2, 3, 4)

b. For Intermediate member (member No. 7)

c. For Vertical Edge Member (members No. 5, 6)

For simplicity in fabrication, use 1" dia. x .125 HSS (Hollow Structural Sections) round, 0.127 in³ for the entire frame.

APPENDIX II. RECOMMENDATION

Protective screens installed under this Standard will not provide complete protection for equipment operators who are sometimes also exposed to such hazards as flying jaggars or other injurious particles which may be projected through the openings of such protective screens. Where such additional hazard exists, it is recommended that the operators be further protected from such flying or intruding objects by the provision of transparent protective shields so mounted on the screens that they can be readily accessible for cleaning without undue impairment to the operator's vision. The grazing materials used in the make-up of the protective shield should have such properties as good luminous transmittance, cleanability and resistance to abrasion, impact, solvents and weather conditions. An example of a plastic meeting the above requirement is Lexan MR 4000 or MR 40T4.

July 24, 1975

ILLUSTRATION I - Example of an "acceptable" screen framework. This framework consists of .150 x 1-1/2 O.D. HSS Round, and is independent of the ROPS.
[Original graphic currently not reproducible. For a paper copy, please contact the Engineering Department of WCB of B.C. at (604) 276 -3114.]

ILLUSTRATION 2 - The side and back screens are made of 1 ga. x 2 woven wire mesh. Intermediate supports have been added to conform to the standard G604. Nominal sizes are: 32" x 22", 32" x 16", (side screens), 32" x 10", 32" x 38" (back screens).
[Original graphic currently not reproducible. For a paper copy, please contact the Engineering Department of WCB of B.C. at (604) 276 -3114.]

TYPICAL SIDE SCREEN GUARD ASSEMBLY

ILLUSTRATION 3 - View from "protected" cab.
[Original graphic currently not reproducible. For a paper copy, please contact the Engineering Department of WCB of B.C. at (604) 276 -3114.]

ILLUSTRATION 4
EXAMPLE OF "WHAT NOT TO DO"
The mesh should not be welded directly to the structural part of the ROPS. Please note the structure shown is not a ROPS.
[Original graphic currently not reproducible. For a paper copy, please contact the Engineering Department of WCB of B.C. at (604) 276 -3114.]

ILLUSTRATION 5
For Terminology Clarification
[Original graphic currently not reproducible. For a paper copy, please contact the Engineering Department of WCB of B.C. at (604) 276 -3114.]

APPENDIX III. ALTERNATE FOR LIGHT DUTY SCREEN

Illustration - Alternate for Light Duty Screen

WCB Standard: G605 Mobile Equipment Half-Doors, March 1990

1. General

1.1. Scope
This standard pertains to any rubber-tired skidders employed in the skidding of logs or tree lengths where the operator may be exposed to flying or other intruding objects.

1.2. Supplementary References
This standard is supplemented by G604 W.C.B. Standard for Light-Duty Screens.

1.3. Purpose
This standard is intended to describe the minimum requirements for the design and selection of structural elements such as plates, stiffeners, sheer deflectors, spring latches or hinges for the half-door.

2. Design Requirements

2.1. General Location
A half-door shall be installed on both side entrances to the control area.

2.2. Dimensions
2.2.1
The entrance opening width shall be a minimum of 46 cm (18 inches). Recommended opening width is 70 cm (27 inches).

2.2.2
The door height shall be a minimum of 60 cm (25 inches) from the floor and having the top of the door at least 25 cm (10 inches) above the cab seat.

2.3. Character (Distinctive Qualities)
2.3.1
The half-door should not sweep the area of the platform or the steps on which the operator must stand to open the door. It shall sweep outward from the cab.

2.3.2
The half-door shall be equipped with a device to cause it to return to its closed position automatically. Also, a latch, preferably of pressure sensitive type should be used to lock the door.

2.3.3
There should be sufficient clearance between the maximum radius of door sweep and the rubber tires of the mobile equipment.

2.3.4
A sheer deflector or stiffener shall be installed on the exterior top edge of the door to act as a deflector/stopper for objects propelled upward.

2.4. Static Strength
2.4.1
The top edge of the door shall be reinforced by a ledge, (sheer deflector), a structural element capable of withstanding a concentrated force of 17800 N (4,000 lbs.) applied at 45° to the horizontal.

2.4.2
Any area of the door shall be designed to resist a 17800 N (4000 lb) static force applied over an area of 62 cm² (9.6 in²).

2.4.3
The hinges, stops and supports shall be adequately designed and fabricated to resist any loads that the door would likely impose upon them. The entire door assembly shall be designed to resist a static force of 17800 N (4,000 lbs.) without causing the door to spring open. On vehicles equipped with a ROPS (Rollover Protective Structure), the door-supporting elements may be attached to parts of the ROPS providing such attachment does not adversely affect the performance of the ROPS. This is contingent on approval by a registered professional engineer.

2.4.4
Weldments shall conform to applicable sections of General Specifications for Welding of Steel Structures CSA W59.1-1970 or most recent version and should be performed by qualified welders only.

2.5. Impact Strength Requirement
All members of the half-door shall be fabricated of material with good impact absorbing properties. The following guideline may be used:

Low carbon content - maximum .28%
High manganese-carbon ratio
Low phosphorus content
Fine grain size
Heat treated
High ultimate energy resistance (Notch tough steel possessing acceptable impact properties)

Examples of steel meeting or exceeding the above requirements:

ASTM A36 or CSA G40.21-38W - for bars, angles and plate
CSA G40.21 42W, 55W - for HSS (Hollow Structural Sections) (CSA G40.16 and G40.17)

3. Structural Details Guidelines

The following recommendations may be used in lieu of clause 2.4.1 and clause 2.4.2

3.1.
Minimum ledge beam size shall be 2 x 2 x .188 HSS, CSA G40.21 42W.

3.2.
Door - steel plate 5 mm (3/16") minimum.

3.3.
Minimum intermediate stiffener size shall be L 2 x 2 x 3/16 CSA G40.21 33W.

3.4.
Maximum spacing of stiffeners is six inches, when L 2 x 2 x 3/16 is used.

Illustration - G605 Half Door (Typical)

WCB Standard: G606 Boom Boat Operator Protective Structures, March 1990

1. General

1.1. Scope
This standard pertains to any vessel used to push or pull logs, booms, bundles or bags in booming ground operation where the operator may be exposed to collision with water-borne logs. Examples of such vessels are dozers, side winders, boom scooters and tugs.

1.2. Purpose
This standard is intended to describe the minimum requirements for the design and selection of window guards, plates, framework and supports for a cab which will form and provide a protective structure for the operator occupying same.

2. Design Principles and Assumptions

The following points are stated to clarify the underlying principles and assumptions of this standard.

2.1.
The stiffness of the vessel is assumed to be in direct proportion to W x GM x SIN q were W is the weight of vessel, GM is the metacentric height, and q is the angle of heel.

2.2.
The stiffness of the operator protective structure is assumed to be very much higher than the vessel's heeling resistance. Hence the stiffness of the entire system is approximately equal to the heeling resistance of the vessel.

2.3.
It is assumed that the elements of the operator protective structure would be arranged in such a way to elastically deflect the projectile rather than arresting its motion.

2.4.
The derivation of the peak collision force is based on linear elastic collisions.

2.5.
It is a minimum requirement for the protective structure to have a "crush protection design capability" to withstand the force exerted on it by a hypothetical blunt log 1 m x 12 m (3 feet x 40 feet) striking end-on at a velocity of 1.5 m/s (5 fps).

Furthermore, there is an impact or strength requirement which is intended to ensure that all members of the cab will have adequate resistance to brittle fracture under cold temperatures.

2.6.
Finally, there is a visibility requirement which is to ensure that the operator's vision will not be seriously obstructed.

2.7.
The operator protective structure can be an integral part of a cab or it can be a "cage" outside an existing structure.

3. Design Loads

3.1.

Imperial Units

3.2.

Metric Units

W = weight of vessel, lbs. or N.

CM = distance from metacentric to hypothetic point of impact, ft. or meters, CM must not be less than 2.1 m (7 ft.).

F = dynamic design load, lbs. or N, less than or equal to the capsizing force.

4. Design Requirements

4.1. Frame
All frame members of the cab protective structure shall be designed to resist the applied load in accordance with clause 3.0 or with some other design criteria acceptable to the Board.

4.2. Cab Skin
All exposed unguarded sides of the cab shall be protected with metal plates or other suitable material. They shall be designed to resist the force as defined in clause 3.0.

4.3. Supports
The cab protective structure shall be secured to the structural parts of the vessel. Such structural parts shall be adequately reinforced to resist the loads imposed on them by the cab protective structure.

4.4. Fastenings
If bolts and nuts are used in the fabrication of the guard, they shall conform to or exceed the ASTM designation A325 requirements.

4.5. Visibility Requirements
The cab shall be equipped with adequate view areas. All such view areas shall be guarded by vertical members spaced at intervals of not more than 6 inches. These vertical members shall be designed to assist the force as defined in clause 3.1.

If flat bars are used as vertical elements, they should be in a radiating pattern to minimize interference with the operator's line of sight.

4.6. Impact Strength Requirement
All members of the half-door shall be fabricated of material with good impact absorbing properties. The following guideline may be used:

low carbon content - maximum .28%
high manganese - carbon ratio
low phosphorous content
fine grain size
heat treated
high ultimate energy resistance (Note: tough steel possessing acceptable impact properties)

Examples of steel meeting or exceeding the above requirements:

ASTM A36 or CSA G40.21 - 38W for bars, angles and plate
CSA G40.21 42W, 55W for HSS (Hollow Structural Sections) (CSA G40.16 and G40.17)

4.7. Weldment
Weldments shall conform to the applicable sections of general specifications for welding of steel structures, CSA W59.1-1970(or latest revision thereof) and shall be performed by licensed welders only.

4.8. Alternate Exit
The operator protective structure shall be provided with an alternate exit. Such exit shall have a minimum clear opening of 60 cm (24 inch) diameter.

4.9. Glazing (optional)
Only safety glass or other suitable material with similar shatter-resistant characteristics shall be used for window areas and such glazing materials shall be positioned at least 20 cm (4 inches) away from the window guard.

5. Minimum Sizes

The following recommended sizes and dimensions may be used in lieu of the design load criteria, clause 3.0.

5.1.
Minimum grid element size shall be 3/4" diameter steel rods or equivalent where a 1 1/4 x 1 1/4 x 0.10 HSS intermediate stiffener is used.

5.2.
Grid element size shall be proportionately increased as the dimension of the guard increases.

5.3.
Minimum column size shall be 3 x 3 x 0.125 HSS depending on the slope and length of the columns. 3 x 3 x 0.25 HSS is strongly recommended.

5.4.
Minimum roof beam size shall be 3 x 3 x 0.125 HSS.

5.5.
Minimum "cab skin" plate size shall be 11 ga to 16 ga depending on the size of intermediate stiffeners used.

5.6.
Gusset plates shall be incorporated where necessary.

5.7.
Materials with equal or better properties may be used in place of those stipulated in this Standard.

G606A BOOMBOAT O.P.S.

G606A Illustration - Boomboat O.P.S. Design

G606B TOWBIT GUARD

G606B Illustration - Towbit Guard Design

WCB Standard: G607 Medium Duty Screen Guard (Front End Log Loader), March 1990

1. General

1.1. Scope
This standard pertains to front end log loaders - mobile machines mounted on a wheeled or tracked chassis, equipped with a front mounted grapple, tusk, or fork-lift device and employed in the loading, unloading, stacking, sorting or handling of logs, used only in dry land sorting areas. For other applications, please refer to G603 Standards for Log Loader and Log Yarder Window Guards.

1.2. Purpose
This standard is intended to describe the minimum requirements for the design and selection of rod-size, framework and supports for guards over window areas of operator's cab.

2. Location of screen guards

2.1.
Front screen guard shall be provided in the area in front of the operator and shall at least extend the full height of all glazing surfaces.

2.2.
Rear screen guard, where necessary and applicable, shall be provided in the area behind the operator.

2.3.
All guards shall be positioned at least four inches away from the glazed windows.

3. Design Requirements

3.1. Strength Requirements
3.1.1 Grid Element
Each vertical element shall be designed to withstand a minimum concentrated point load of 300 lbs. being applied at a location producing the greatest critical stresses. There should be at least three vertical elements.

3.1.2 Perimeter Frame
The outer frame shall consist of sections with the following section modulus:

Perimeter frame modulus in metric and imperial measure

S = edge beam section modulus (cm³) (in³)
W = dimension of guard (cm) (in)
f = allowable working stress MPa (psi)

3.1.3 Supports
The perimeter frame shall be secured to the structural parts of the cab. Such structural parts shall be adequately designed and constructed to resist all loads imposed on them by the guards.

On the front end loaders equipped with a rollover protective structure (ROPS), the screen guards may be attached to parts of the ROPS, provided that such attachment does not adversely affect the performance of the ROPS. All such attachments shall be clamped unless welding is permitted by the ROPS manufacturer or a registered professional engineer.

3.1.4 Fastenings
If nuts and bolts are used in the fabrication of the guard, they shall conform to or exceed the ASTM Designation A325 requirements.

3.2. Impact Strength Requirement
All members of the guard shall be made of material with good impact absorbing properties. The following guideline may be used:

Low carbon content (less than 0.28%)
High ratio of manganese to carbon
Low phosphorous content
Fine grain size
Heat treated
High ultimate energy resistance

Examples of steel meeting or exceeding the above requirements:

ASTM A36, CSA G40.21 33G, 44W - for plates, bars and angles.
CSA 40.21 50W - for HSS (Hollow Structural Sections)

4. Visibility Requirement
Minimum interference with operator's visibility shall be one of the governing criteria in the design and positioning of the vertical members of the guard. If flat bars are used as grid elements, they should be in a radiating pattern in line with the operator's line of sight. The clearance between vertical elements shall not be greater than eight inches.

5. Minimum Recommended Sizes

Vertical elements cross-section size should not be less than 19 mm (3/4") diameter mild steel rod or 16 mm (5/8") square rod.
The openings between adjacent vertical members should not be greater than eight inches.
The perimeter frame cross-section size should not be less than 2 x 2 x .150 square hollow structural section (HSS) 50,000 psi yield or 3 x 3 x 5/16 square angle, 36,000 psi yield.

6. Weldment
Weldments shall conform to applicable sections of General Specification for Welding of Steel Structures, CSA W59.1-1970 (or latest revision thereof) and shall be performed by licensed welders only.

Illustration - Weldment Typical Design

Typical Design
For Illustration Only

WCB Standard: G608 Mobile Equipment Roof Structures - Heavy Duty, March 1990

1. General

1.1. Scope
This standard pertains to mobile industrial or logging equipment where the operator may be exposed to hazards caused by falling objects such as tree trunks, snags, limbs, rocks, etc. It is also supplementary to G602 Standard for Log Loader and Log Yarder Raised Cabs.

1.2. Purpose
This standard is intended to describe the minimum requirements for the design and selection of plates and stiffeners for roof construction. Refer to the aforementioned G602 Standard for details on substructure construction.

2. Design Criteria

2.1. Option One - Testing Method
The roof shall be designed to meet the Minimum Performance Criteria for Falling Object Protective Structure (FOPS) - SAE J231.

2.2. Option Two - Analytical Methods
The roof shall be designed to absorb 11500 J (8,500 ft-lb) of impact energy without allowing a projectile measuring 20 cm (8 in) in diameter to penetrate into the DLV as defined in SAE J397a.

2.3. Option Three - Minimum Recommended Size
The roof shall be designed in accordance with the minimum recommended size as outlined in §4.0.

3. Design Requirements

3.1. Superstructure of Roof
The superstructure shall be designed in accordance with the design criteria as outlined in §2.0.

3.2. Substructure of Roof
All frame members and supports of the Cab Protective Structure shall be designed to resist the applied load in accordance with G602. This applies to all mobile equipment covered by G602. Equipment covered by SAE J1040 shall be designed in accordance with SAE J1040 or its equivalent.

3.3. Alternate Exit
The operator protective structure shall be provided with an alternate exit. Such exit shall have a minimum clear opening of 60 cm (24 in) diameter.

3.4. Impact Strength Requirement
All members of the guard shall be made of material with good impact absorbing properties. The following guideline may be used:

Low carbon content (less than 0.28 %)
High ratio of manganese to carbon
Low phosphorous content
Fine grain size
Heat treated
High ultimate energy resistance

Examples of steel meeting or exceeding the above requirements:

CSA G40.21 33G, 44W - for plates, bars and angles
CSA G40.21 50W - for HSS (Hollow Structural Sections)

3.5. Weldments
Weldments shall conform to applicable sections of General Specification for welding of Steel Structures, CSA W59.1-1970 (or latest revision thereof) and shall be performed by licensed welders only.

4. Minimum Recommended Sizes

4.1. Option One - Plate Method
The following are designed on the assumption that stiffeners will be used to limit the unstiffened areas not to exceed 700 sq. in. (4516 sq. cm)

4.1.1
Minimum thickness of roof plate shall be 3/16 in. (4.76 mm)

4.1.2
Minimum section modulus of stiffeners used shall be 0.19 in³, (3.11 cm³) i.e. L 2 x 2 x 3/16

4.2. Option Two - Grid Method
Minimum rod size shall be 3/4 inch round bars or 5/8 inch square bars. Each grid opening shall not be greater than 413 cm² (64 square inches.) A light gauge roof plate is recommended in conjunction with the grid.

WCB Standard: G609 Mobile Equipment Roof Structures - Light Duty, March 1990

1. General

1.1. Scope
This Standard pertains to mobile industrial equipment exposed to hazards from falling objects such as bricks, concrete blocks, and hand tools that may fall from relatively low heights encountered in operations such as highway maintenance or landscaping and other services on construction sites.

1.2. Purpose
This standard is intended to describe the minimum requirement for the design and selection of plates for roof construction.

2. Design Criteria

2.1. Option One - Testing Method
The roof shall be designed to the Minimum Performance Criteria for Falling Object Protective Structure (FOPS) for Industrial Equipment - SAE J1043.

2.2. Option Two - Minimum Recommended Size
The roof shall be designed in accordance with the minimum recommended size as outlined in §4.0.

3. Design Requirements

3.1.
The roof plate shall be designed in accordance with the design criteria as outlined in §2.0.

3.2.
All frame members and supports of the Cab Protective Structure shall be designed to resist the applied load. Equipment covered by SAE J1040 shall be designed in accordance with SAE J1040 or its equivalent.

3.3. Weldments
Weldments shall conform to applicable sections of General Specifications for welding of Steel Structures, CSA W59.1-1970 (or latest revision thereof) and shall be performed by licensed welders only.

4. Minimum Recommended Sizes

Minimum thickness of roof plate shall be 10 ga, equivalent to 3.4 mm (0.1345 in).

The above is designed on the assumption that stiffeners will be used to limit the unstiffened areas not to exceed 7740 cm² (1200 in²).

WCB Standard: LDR 1-2004 Job Built Ladders

1. Scope

This Standard only applies to portable wooden ladders built for use by workers at a job site. This Standard does not apply to ladders which change ownership through sale or otherwise.

Figure 1: Job Built Ladder up to 5 m (16 ft.) Long

2. Design

A portable wooden ladder made at the job site must meet the following minimum requirements.

2.1 Side rails

2.2 Rungs

3. Ladder components and coating

Standard Grading Rules for Canadian Lumber

WCB Standard: PPE 1 - 1997 Leg Protective Devices (Amended January 2008)

1. Scope

This standard provides specifications and performance criteria for leg protection for a worker using a chain saw.

2. Definitions

Leg protection means personal protective equipment worn for protection from leg injury due to contact with a moving saw chain.

3. Types

Pant type - the protection material is secured to and held in position by the trousers.

Apron type - the protection material is secured to an apron style garment normally worn outside the trousers and secured around the worker's legs and waist.

Chap type - the protection material is secured to a chap style garment normally worn outside the trousers and secured around the worker's legs.

4. General Requirements

4.1
Leg protection must be of materials suitable for the intended application. The use of the leg protection must not unduly restrict the manoeuvrability of the worker. Leg protection must not shrink more than 10% when cleaned in accordance with the manufacturer's instructions during its service life.

4.2
The protective material of leg protection must be at least 711 mm (28 in) long and a width covering 180° in the front of both legs from inseam to outseam plus 100 mm (4 in) on the left side of both legs.

If the 28" length requirement results in a tripping hazard, the protective pad can be shorter, as long as it covers an area extending from the crotch to within 75 mm (3 in) of the centre of the ankle. (As amended August 2002).

4.3
When leg protection is worn by a worker, the protective material must extend at minimum from the crotch to within 75 mm (3 in) of the ankle. The protective material must be effectively secured in this position.

4.4
Effective measures must be taken to prevent unravelling or fraying of material along any edges or other area where unravelling or fraying is likely to occur.

NOTE: When a "heat seal" is used to control unravelling or fraying of synthetic fibres, the "heat seal" must be effective over the life of the product. A heat seal subject to cracking must be covered to prevent abrasion of the wearer's skin.

5. Performance Requirements

5.1
Leg protection must meet the requirements of the "Threshold Chain Speed" Test. Tests must be done on leg protection samples assembled in the manner which the leg protection will be produced for distribution.

5.2 "Threshold Chain Speed" Test

NOTE: The threshold chain speed is the chain speed at which rapid cut-through occurs and below which cut-through consistently requires 1.01 seconds or more.

5.2.1
When tested, as described in clause 5.2.2, leg protection must have a threshold chain speed of 1098 m/min (3,600 ft/min) or more.

5.2.2 Test Method
5.2.2.1
The test apparatus must have

5.2.2.2
The test procedure is

6. Identification

Leg protection must be permanently marked on the exterior of the leg protection with characters at least 6 mm (¼ in) high to show the manufacturer's name or recognized trademark, the design specification standard, and the performance standard and level met by the protective material. The year of manufacture must be included on a label or be otherwise marked on the garment.

NOTE: The label must include garment level of performance. Some sample wording is "Meets WCB of BC PPE 1, 1997[3600]" or "Meets WCB of BC PPE 1, 1997-ASTM F1414-04[CS50-3300]" or "Meets WCB of BC PPE 1, 1997-ISO 11393-2 Class 2" or "Meets WCB of BC PPE 1, 1997-EN 381-5 (1995)[Class 2]" or similar wording.

For example, a garment that is manufactured to the design sepcification of the WCB PPE 1 standard and meets the performance requirements for Class 2 garments in the ISO 11393-2 standard could incorporate a garment label as follows:

Sample PPE 1 garment label

7. Care and Maintenance

7.1
Instructions on the proper care, maintenance and repair of leg protection must be provided by the manufacturer.

7.2
Leg protection which shows damage which will affect its performance must be removed from service.

NOTE: Test procedures and ratings for threshold chain speed may differ depending on the standard referenced; however performance in the field may be similar. Comparisons of performance are best made by comparison of threshold chain speed numbers obtained using the same test method. Under these circumstances, the higher the chain speed the greater the cut protection.

WCB Standard: PPE 2 High Visibility Garment - Personal Protective Equipment Standard 2

This following standard outlines minimum requirements for three types of high visibility garments acceptable to the Workers' Compensation Board of British Columbia.

In this standard, the following definitions apply:

Background: The part of the garment visible either from the front or the back of the garment when the fully assembled garment is laid flat for inspection, not including the area of the VE trim.

Coefficient of Retroreflection: The fraction of incident light reflected by a retroreflective surface per unit area. The unit of measurement is candelas per foot candle per square foot as measured at 0.2 degrees observation angle and -4.0 degrees entrance angle measured in accordance with ASTM E809 - "Standard Practice for Measuring Photometric Characteristics of Retroreflectors".

Florescent Material: A material that absorbs ultraviolet radiation in daylight and emits it in the visible light region. This property allows the material to radiate more visible light than is incident on it. Therefore, it looks and is brighter than a non-florescent material which, at best, can reflect all the visible light that falls on it.

Retroreflective Material: A material that reflects light back to the same direction as the source of the light.

Type 1: Vest, shirt or other similar garment worn on the torso with a florescent background and attached VE trim.
Type 2: Jacket, coat, coverall or other garment with a bright colored background and attached VE trim.
Type 3: A harness type garment worn on the torso, fabricated from parallel strips of contrasting colors. The harness has florescent and retroreflective properties.

VE Trim: Visibility enhancing trim attached to the garment. The trim has florescent and retroreflective properties.

Application

This standard does not apply to firefighters. High visibility garments for firefighters is provided for in the standard NFPA 1971, "Standard on Protective Clothing for Structural Firefighters".

Requirements Applying To All Types of High Visibility Garments

The background material in florescent or bright color in yellow, orange or red must meet the chromaticity coordinates and minimum luminance factor specified in Table 1.

No part of the garment may melt, separate or ignite when subjected to 500 degrees Fahrenheit air temperature for 5 minutes for high visibility garment used in environments where exposure to elevated temperatures or open flames is possible.

Where a worker is engaged in welding or burning operations, the high visibility garment must be made from flame retardant materials.

In an environment where loose fitting clothing may be caught by moving equipment or other stationary objects, high visibility garments must have "tear away" properties. An example of this is the use of Velcro^TM strips for the fastening of the garment.

Where high visibility garments are used in potentially explosive environments, Velcro^TM strips must not be used due to static electricity concerns.

All high visibility garments must be worn outside of all other clothing and must be fully fastened closed.

If the background material is of open weave construction the largest dimension in the openings of the background material must not exceed 3.2 mm (1/8 inch).

VE trim must not be of open weave construction.
VE trim must:

Have a smooth flat exterior finish.
Be securely attached to the garment.
Be applied so that it is visible on the side of the garment when worn.

There must be a minimum of 77 square centimeters (12 square inches) of VE trim within a defined area below the arm hole. The defined area below the arm hole consists of a 152 mm (6 inch) wide vertical strip centered about the center line of the arm hole.
In lieu of side VE trim, a band of 50 mm (2 inches) wide VE trim may be placed around the sleeve at the wrist or upper arm area of the garment.

Be applied to form one vertical stripe on either side on the front of the garment and an "X" pattern on the back of the garment.
Be at least 50 mm (2 inches) wide.
Be made either from; combined performance material that exhibits both florescent and retroreflective properties, or separate florescent and retroreflective materials.

The florescent portion of the trim must be florescent lime yellow if the background color is florescent orange, orange or red and must be florescent orange if the background color is florescent lime yellow, florescent yellow or bright yellow.
The retroreflective portion of the VE trim must be continuous along the entire length of the trim and have a minimum Coefficient of Retroreflection = 240 divided by the width in inches of the retroreflective portion of the VE trim.( e.g. if the width of the retroreflective portion is 1/2 inch, the minimum Coefficient of Retroreflection is 480)

Type 1 Garments

The garment background must be florescent lime yellow, florescent yellow, or florescent orange colored.

The minimum vertical length for both front and back of the garment is 0.61 metres (24 inches).

The minimum background area for either the front or the back of the garment is 0.13 square metres (200 square inches).

The florescent portion of the VE trim for either the front or the back of the garment must have a minimum area of 0.05 square metres (80 square inches).

Type 2 Garments

The background of the garment must be either florescent lime yellow, florescent yellow, bright yellow, florescent orange, bright orange or bright red.

The minimum vertical length for both front and back of the garment is 0.61 metres (24 inches).

The minimum background area for either the front or the back of the garment is 0.258 square metres (400 square inches).

The florescent portion of the VE trim for either the front or the back of the garment must have a minimum area of 0.05 square metres (80 square inches).

Type 3 Garments

The garment background must be florescent lime yellow, florescent yellow, or florescent orange colored.

The minimum background area for either the front or the back of the garment is 0.064 square metres (100 square inches).

The minimum vertical length for both front and back of the garment is 0.51 metres (20 inches).

The florescent portion of the VE trim for either the front or the back of the garment must have a minimum area of 0.064 square metres (100 square inches).

The garment must be designed so that there is color contrast along the entire length of at least one side of the VE trim.

Police Forces and Other Emergency Response Personnel

It is anticipated that police forces and other emergency response personnel may require greater protection in the hours after dark due to the nature of their job function. In lieu of requirements 4, 5 and 6 above on the pattern, width and color of the VE trim specified, the VE trim used by these personnel for all garment types must:

Have a minimum area of 0.05 square metres (80 square inches) for either