22.H Horse Scaffolds.
22.H.01 Horses must not be constructed or arranged more than two tiers or 10 ft (3 m) in height: scaffolds must be 5 ft (1.5 m) or less in height and 5 ft (1.5 m) or more in width. When tiered heights exceed 6 ft (1.8 m), FP must be used.
22.H.02 The members of horse scaffolds must not be less than those specified in Table 22-2.
| Minimum Dimensions for Horse Scaffold Members | ||
|---|---|---|
| Members | Dimensions | |
| Horizontal members of bearers | 3 x 3.9 in (7.6 x 10 cm) | |
| Legs | 2 x 3.9 in (5 x 10 cm) | |
| Longitudinal brace between legs | 1 x 5.9 in (2.5 x 15 cm) | |
| Gusset brace at top of legs | 1 x 7.9 in (2.5 x 20 cm) | |
| Half diagonal braces | 2 x 3.9 in (5 x 10 cm) | |
22.H.03 Horse scaffolds must be spaced not more than 5 ft (1.5 m) for medium duty and not more than 8 ft (2.4 m) for light duty.
22.H.04 When arranged in tiers, each horse scaffold must be placed directly over the horse scaffold in the tier below. The legs must be nailed or otherwise secured to the planks to prevent displacement or thrust and each tier must be cross braced.
22.H.05 Weakened or defective components must not be used.
22.I Pump Jack Scaffolds.
22.I.01 Pump jack scaffolds must be designed for a minimum working load of 500 lbs (226.8 kg) and not more than two (2) workers must be allowed on the scaffold at one time.
22.I.02 Pump jack brackets, braces, and accessories must be fabricated from metal plates and angles and installed in accordance with the manufacturer's recommendations. Installation and operational manuals must be maintained onsite and made available upon request of the GDA.
22.I.03 The standing platform must be fully decked and the planking secured. Platforms thicker than 2 in (5.08 cm) must not be overlapped.
22.I.04 The minimum width of a standing platform must be 18 in (45.7 cm) and the work bench must be 12 in (30.4 cm).
22.I.05 All materials on the work bench must be secured from falling.
22.I.06 Pump jack scaffolds must be provided with a guardrail system as specified by the manufacturer. Personal fall arrest systems may be used in lieu of guardrails.
22.I.07 When a workbench is used at an approximate height of 42 in (1.06 m), the top rail may be eliminated if the workbench is fully decked, if the workbench is secured, and if it is capable of withstanding 200 lbs (90.7 kg) force in any direction.
22.I.08 Workbenches must not be used as a standing platform.
22.I.09 A ladder must be provided for access to the platform.
22.I.10 All poles must be supported by sills or other foundations adequate to support the load.
22.I.11 Poles.
- Pole lumber must be 2-in x 4-in (5-cm x 10.1-cm) stock, of Douglas fir, or equivalent, straight-grained, clear, free of cross-grain, shakes, large loose or dead knots, and other defects that might impair strength.
- Wood poles must not exceed 30 ft (9.1 m) in height; and spacing cannot exceed 7 ft
- (2.1 m).
- Metal poles must not exceed 50 ft (15.2 m) in height unless the design is approved by an RPE. The spacing of metal poles in excess of 7 ft (2.1 m) must also be determined by an RPE.
- When poles are constructed of two continuous lengths they must be of 2-in x 4-in (5- cm x 10.1-cm) (kiln dried straight grain fir) or equivalent, spiked together with the seam parallel to the pump jack, and with 10d common nails, 12 in (30.4 cm) center-to-center, staggered uniformly from opposite outside edges.
- 4-in by 4-in (10.1 cm by 10.1 cm) wood poles may not be spliced to increase the length of any individual member.
- Poles must be secured to the wall by triangular bracing, or equivalent, at the bottom, top, and other points to provide a maximum vertical spacing of not more than 10 ft (3 m) between braces. Each brace must be capable of supporting a minimum of 225 lbs (102 kg) tension or compression.
- When wood scaffold planks are used as platforms, poles used for pump jacks must not be spaced more than 10 ft (3 m) on center. When fabricated platforms are used that comply with all other provisions of this Section, pole spacing may exceed 10 ft on center if permitted by the manufacturer.
- Poles must not be placed closer than 10 ft (3.04 m) of power lines or electrical conductors until such are insulated, de-energized, or otherwise rendered safe against contact. > See Table 11-1.
22.I.12 Brackets.
- Each pump jack bracket must have two positive gripping mechanisms to prevent any failure or slippage.
- For the pump jack bracket to pass bracing already installed, an extra brace must be used approximately 4 ft (1.2 m) above the one to be passed until the original brace is reinstalled.
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22-11. What is allowed when using Pump Jack Scaffolds?
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