General Requirements

     Working Loads

AFOSH 91-501 16.5.1.2.1. (exceeds OSHA 1910.29(a)(2)(ii)(a)) The design working load of ladder stands will be calculated on the basis of one or more 250-pound persons with 50 pounds of equipment each.

OSHA 1910.29(a)(2)(ii)(b) and AFOSH 91-501 16.5.1.2.2 The design load of all scaffolds shall be calculated on the basis of:
     Light - Designed and constructed to carry a working load of 25 pounds per square foot.
     Medium - Designed and constructed to carry a working load of 50 pounds per square foot.
     Heavy - Designed and constructed to carry a working load of 75 pounds per square foot.
All ladder stands and scaffolds shall be capable of supporting at least four times the design working load. [NOTE: If you're not certain whether your stand meets this requirement, ask to see the manufacturer's load test certificate verifying the platform can withstand four times the working load rating.]

OSHA 1910.29(a)(2)(v) and AFOSH 91-501 16.5.1.5 All exposed surfaces shall be free from sharp edges, burrs or other safety hazards.

     Work Levels

OSHA 1910.29(a)(3)(i) and AFOSH 91-501 16.5.2.1 The maximum work level height shall not exceed four (4) times the minimum or least base dimensions of any mobile ladder stand or scaffold. Where the basic mobile unit does not meet this requirement, suitable outrigger frames shall be employed to achieve this least base dimension, or provisions shall be made to guy or brace the unit against tipping.

OSHA 1910.29(a)(3)(ii) and AFOSH 91-501 16.5.2.2 The minimum platform width for any work level shall not be less than 20 inches for mobile scaffolds (towers). Ladder stands shall have a minimum step width of 16 inches.

OSHA 1910.29(a)(3)(iii) and AFOSH 91-501 16.5.2.3 The supporting structure for the work level shall be rigidly braced, using adequate cross bracing or diagonal bracing with rigid platforms at each work level.

OSHA 1910.29(a)(3)(iv) and AFOSH 91-501 16.5.2.4 The steps of ladder stands shall be fabricated from slip resistant treads.

OSHA 1910.29(a)(3)(v) and AFOSH 16.5.2.5 The work level platform of scaffolds (towers) shall be of wood, aluminum, or plywood planking, steel or expanded metal, for the full width of the scaffold, except for necessary openings. Work platforms shall be secured in place. All planking shall be 2-inch (nominal) scaffold grade minimum 1,500 f. (stress grade) construction grade lumber or equivalent.

OSHA 1910.23(c)(1) Every open-sided floor or platform 4 feet or more above adjacent floor or ground level shall be guarded by a standard railing on all open sides except where there is entrance to a ramp, stairway, or fixed ladder. The railing shall be provided with a toeboard wherever, beneath the open sides,
     1910.23(c)(1)(i) Persons can pass,
     1910.23(c)(1)(ii) There is moving machinery, or
     1910.23(c)(1)(iii) There is equipment with which falling materials could create a hazard.

AFOSH 91-501 16.5.2.6. (encompasses OSHA 1910.29 (a)(3)(vi) and (vii) and AFOSH 91-100 8.3.4.10.7) Scaffold work platforms at work levels 10 feet or higher will have guardrails, midrails, and toeboards which meet the requirements outlined in paragraph 16.4.6.10.
     REF: 16.4.6.10. Platforms other than buckets or baskets shall include a guardrail system:
         16.4.6.10.1. The guardrail system shall include a top rail around its upper periphery. The top rail shall be 42 inches high, above the platform surface, designed to withstand 300 pounds of force.
         16.4.6.10.2. The guardrail system shall include at least one rail approximately midway between the top rail and the platform surface, designed to withstand 300 pounds of force.
         16.4.6.10.3. The platform shall include toeboards on all sides. The minimum toeboard height shall be 4 inches. Toeboards may be omitted at the access opening.
         16.4.6.10.4. The configuration of the aerial platform shall include access for personnel entering the platform when it is in the lowered position. Access steps or rungs shall have a slip-resistant surface. Flexible materials such as cables, chains, and rope may be used across access openings not more than 30 inches wide.

OSHA 1910.29(a)(3)(viii) and AFOSH 91-501 16.5.2.7 A climbing ladder or stairway shall be provided for proper access and egress, and shall be affixed or built into the scaffold and so located that its use will not have a tendency to tip the scaffold. A landing platform shall be provided at intervals not to exceed 30 feet.

     Wheels or Casters

OSHA 1910.29(a)(4)(i) and AFOSH 91-501 16.5.4.1 Wheels or casters shall be properly designed for strength and dimensions to support four (4) times the design working load.

OSHA 1910.29(a)(4)(ii) and AFOSH 91-501 16.5.4.2. Scaffold casters will be provided with a positive wheel and (or) swivel lock to prevent movement. Two of the four casters on ladder stands will be lockable and the swivel type.

OSHA 1910.29(a)(4)(iii) and AFOSH 91-501 16.5.4.3 Where leveling of the elevated work platform is required, screw jacks or other suitable means for adjusting the height shall be provided in the base section of each mobile unit.

AFOSH 91-501 16.5.4.4. A minimum of two brakes, wheel locks, or permanently installed jacks will be operable on all mobile work platforms.

Mobile Tubular Welded Frame Scaffold

OSHA 1910.29(b)(2) and AFOSH 91-501 16.5.5.2 "Bracing." Scaffolds shall be properly braced by cross braces and/or diagonal braces for securing vertical members together laterally. The cross braces shall be of a length that will automatically square and align vertical members so the erected scaffold is always plumb, square, and rigid.

Mobile Work Platforms

AFOSH 91-100 8.2.5.6. Mobile Work Platforms. Mobile work platforms shall have protective guardrails, midrails and toe boards (or equivalent) installed on all open sides, except the side facing the aircraft when it is within 14 inches of the working surface, unless workers are protected by a PFAS.

OSHA 1910.29(e)(2) and AFOSH 91-501 16.5.8.2 "Base width." The minimum width of the base of mobile work platforms shall not be less than 20 inches.

OSHA 1910.29(e)(3) and AFOSH 91-501 16.5.8.3 "Bracing." Adequate rigid diagonal bracing to vertical members shall be provided.

Mobile Ladder Stands

OSHA 1910.29(f)(2) and AFOSH 91-501 16.5.9.2 "Base width." The minimum base width shall conform to OSHA 1910.29 (a)(3)(ii). The maximum length of the base section shall be the total length of combined steps and top assembly, measured horizontally, plus five-eighths inch per step of rise.

OSHA 1910.29(f)(3) and AFOSH 91-501 16.5.9.3 "Steps." Steps shall be uniformly spaced, and sloped, with a rise of not less than nine (9) inches, nor more than ten (10) inches, and a depth of not less seven (7) inches. The slope of the steps section shall be a minimum of fifty-five (55) degrees and a maximum of sixty (60) degrees measured from the horizontal. [NOTE: OSHA interpretations indicate that this minimum slope requirement is not applicable to platforms with variable-pitch stairs, as their unique design necessitates a slope that can vary from practically flat to the full 60-degree elevation. There is currently no standard that specifically addresses variable-pitch staircases.]

AFOSH 91-501 16.5.9.4. Handrails:
     16.5.9.4.1. (exceeds OSHA 1910.29(f)(4)(i)) Units having more than four steps or 60 inches vertical height to the top step will be equipped with handrails.
     16.5.9.4.2. and OSHA 1910.29(f)(4)(ii) Handrails will be a minimum of 29 inches high and will be the same height all along the step. Measurements will be taken vertically from the center of the step.
     16.5.9.4.3. Load design will meet requirements of AFOSH 91-501 16.5.1.2.1.

OSHA 1910.29(f)(5) “Loading." The load (see OSHA 1910.29 (a)(2)(ii)(a)) shall be applied uniformly to a 3 1/2 inches wide area front to back at the center of the width span with a safety factor of four (4).

Mobile Work Platforms and Ladder Stands

AFOSH 91-501 16.5.10.3 Removable protective guardrails, (midrails when required), and toeboards may be provided on mobile work platforms in lieu of those permanently affixed. Work platforms positioned 14 or more inches from the working surface (i.e., aircraft, buildings) will have guardrails (and toeboards, if work levels are 10 feet or higher above the ground or floor) installed on all open sides. Guardrails and toeboards will meet the criteria of paragraph 16.4.6.10.3. and will be used on all work platforms.

AFOSH 91-501 16.5.10.4  Prior to any user ascending to a raised portion of a mobile platform, all locking devices (i.e., pins, collars, etc.) will be installed; hydraulic pressure shall be released and the platform slowly lowered until locking devices are securely engaged; and hydraulic pressure valve(s) shall be closed. If the raisable portion of the platform cannot be elevated from ground level, the user may ascend to that platform portion and adjust the platform height. However, prior to any task or work being started, the requirements for locking devices, pressure release, and closing valves will be met.