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296-24-23531  <<  296-24-23533 >>   296-24-237

Crane and derrick suspended personnel (work) platforms.

(1) Scope and application. This standard applies to the design, construction, testing, use and maintenance of personnel platforms, and the hoisting of personnel platforms on the load lines of cranes or derricks.
(2) Definitions. For the purposes of this section, the following definitions apply:
(a) "Failure" means load refusal, breakage, or separation of components.
(b) "Hoist" (or hoisting) means all crane or derrick functions such as lowering, lifting, swinging, booming in and out or up and down, or suspending a personnel platform.
(c) "Load refusal" means the point where the ultimate strength is exceeded.
(d) "Maximum intended load" means the total load of all employees tools, materials, and other loads reasonably anticipated to be applied to a personnel platform or personnel platform component at any one time.
(e) "Runway" means a firm, level surface designed, prepared, and designated as a path of travel for the weight and configuration of the crane being used to lift and travel with the crane suspended platform. An existing surface may be used as long as it meets these criteria.
(3) General requirements. The use of a crane or derrick to hoist employees on a personnel platform is prohibited, except when the erection, use, and dismantling of conventional means of reaching the worksite, such as a personnel hoist, ladder, stairway, aerial lift, elevating work platform or scaffold, would be more hazardous, or is not possible because of structural design or worksite conditions.
(4) Operational criteria.
(a) Hoisting of the personnel platform shall be performed in a slow, controlled, cautious manner with no sudden movements of the crane or derrick, or the platform.
(b) Load lines shall be capable of supporting, without failure, at least seven times the maximum intended load, except that where rotation resistant rope is used, the lines shall be capable of supporting without failure, at least ten times the maximum intended load. The required design factor is achieved by taking the current safety factor of 3.5 and applying the fifty percent derating of the crane capacity.
(c) Load and boom hoist drum brakes, swing brakes, and locking devices such as pawls or dogs shall be engaged when the occupied personnel platform is in a stationary working position.
(d) Cranes and derricks with variable angle booms shall be equipped with a boom angle indicator, readily visible to the operator.
(e) Cranes with telescoping booms shall be equipped with a device to indicate clearly to the operator, at all times, the boom's extended length, or an accurate determination of the load radius to be used during the lift shall be made prior to hoisting personnel.
(f) A positive acting device shall be used which prevents contact between the load block or overhaul ball and the boom tip (anti-two-blocking device), or a system shall be used which deactivates the hoisting action before damage occurs in the event of a two-blocking situation (two block damage prevention feature).
(g) The load line hoist drum shall have a system or device on the power train, other than the load hoist brake, which regulates the lowering rate of speed of the hoist mechanism (controlled load lowering). Free fall is prohibited.
(h) The crane shall be uniformly level within one percent of level grade and located on firm footing. Cranes equipped with outriggers shall have them all fully deployed following manufacturer's specifications, insofar as applicable, when hoisting employees.
(i) The total weight of the loaded personnel platform and related rigging shall not exceed fifty percent of the rated capacity for the radius and configuration of the crane or derrick.
(j) The use of machines having live booms (booms in which lowering is controlled by a brake without aid from other devices which slow the lowering speeds) is prohibited.
(k) Multiple-part line block: When a multiple-part line block is in use, a substantial strap shall be used between the crane hook and common ring, shackle, or other equivalent device, to eliminate employee exposure to the lines running through the block, and to the block itself.
(5) Rigging.
(a) Lifting bridles on box-type platforms shall consist of four legs of equal length, with one end securely shackled to each corner of the platform and the other end securely attached to a common ring, shackle, or other equivalent device to accommodate the crane hook, or a strap to the crane hook.
(b) Shackle bolts used for rigging of personnel platforms shall be secured against displacement.
(c) A substantial safety line shall pass through the eye of each leg of the bridle adjacent to the common ring, shackle, or equivalent device and be securely fastened with a minimum amount of slack to the lift line above the headache ball or to the crane hook itself.
(d) All eyes in wire rope sling shall be fabricated with thimbles.
(e) Wire rope, shackles, rings, master links, and other rigging hardware must be capable of supporting, without failure, at least five times the maximum intended load applied or transmitted to that component. Where rotation resistant wire rope is used for slings, they shall be capable of supporting without failure at least ten times the maximum intended load.
(f) Hooks on headache ball assemblies, lower load blocks, or other attachment assemblies shall be of a type that can be closed and locked, eliminating the hook throat opening. Alternatively, an alloy anchor type shackle with a bolt, nut, and retaining pin shall be used.
(g) Bridles and associated rigging for attaching the personnel platform to the hoist line shall be used only for the platform and the necessary employees, their tools and the materials necessary to do their work, and shall not be used for any other purpose when not hoisting personnel.
(6) Personnel platforms - design criteria.
(a) The personnel platform and suspension system shall be designed by a qualified engineer or a qualified person competent in structural design.
(b) The suspension system shall be designed to minimize tipping of the platform due to movement of employees occupying the platform.
(c) The personnel platform itself, except the guardrail system and body belt/harness anchorages, shall be capable of supporting, without failure, its own weight and at least five times the maximum intended load based on a minimum allowance of five hundred pounds for the first person with light tools, and an additional two hundred fifty pounds for each additional person.
(d) Criteria for guardrail systems and body belt/harness anchorages are contained in Parts J-1 and J-2 of this chapter.
(e) The personnel platform shall be conspicuously posted with a plate or other permanent marking which indicates the weight of the platform and its rated load capacity or maximum intended load.
(7) Platform specifications.
(a) Each personnel platform shall be equipped with a guardrail system which meets the requirements of WAC 296-24-75007, and shall be enclosed at least from the toeboard to mid-rail with either solid construction or expanded metal having openings no greater than one-half inch (1.27cm).
(b) A grab rail shall be installed inside the entire perimeter of the personnel platform.
(c) Access gates, if installed, shall not swing outward during hoisting.
(d) Access gates, including sliding or folding gates, shall be equipped with a restraining device to prevent accidental opening.
(e) Headroom shall be provided which allows employees to stand upright in the platform.
(f) In addition to the use of hard hats, employees shall be protected by overhead protection on the personnel platform when employees are exposed to falling objects.
(g) All rough edges exposed to contact by employees shall be surfaced or smoothed in order to prevent injury to employees from punctures or lacerations.
(h) All welding of the personnel platform and its components shall be performed by a qualified welder familiar with the weld grades, types, and material specified in the platform design.
(i) Occupants of all personnel platforms shall wear a safety belt or harness and lanyard which meets the requirements of ANSI A10.14-1975.
(j) Box-type platform: The workers lanyard shall be secured to the work platform or guardrail of the work platform.
(k) Rescue platform:
(i) If the platform is used as a rescue vehicle, the injured worker shall be strapped into the stretcher or basket.
(ii) The basket shall then be secured by lanyard to an anchorage within the platform.
(l) Boatswains chair: The workers lanyard shall be secured to the lift line above the headache ball or to the crane hook itself.
(m) Barrel-type platform:
(i) The workers lanyard shall be secured to the lift line above the headache ball or to the crane hook itself.
(ii) A solid bar or rod shall be substantially attached in a rigid position to the bottom or side of the platform.
(iii) The side bar or rod shall extend a minimum of eight feet above the floor of the work platform.
(iv) The bottom of the barrel-type platform shall be of a convex shape to cause the platform to lay on its side when lowered to the ground or floor.
(v) Workers shall enter and exit from barrel-type platforms only when they are in an upright position, stable, and securely attached to the load line.
(vi) The employer shall use methods or devices which allow employees to safely enter or exit barrel-type platforms.
(8) Personnel platform loading.
(a) The personnel platform shall not be loaded in excess of its rated load capacity.
(b) The number of employees occupying the personnel platform shall not exceed the number required for the work being performed.
(c) Personnel platforms shall be used only for employees, their tools, and the materials necessary to do their work, and shall not be used to hoist only materials or tools when not hoisting personnel.
(d) Materials and tools for use during a personnel lift shall be secured to prevent displacement.
(e) Materials and tools for use during a personnel lift shall be evenly distributed within the confines of the platform while the platform is suspended.
(9) Trial lift, inspection, and prooftesting.
(a) A trial lift with the unoccupied personnel platform loaded at least to the anticipated liftweight shall be made from ground level, or any other location where employees will enter the platform, to each location at which the personnel platform is to be hoisted and positioned. This trial lift shall be performed immediately prior to placing personnel on the platform. The operator shall determine that all systems, controls, and safety devices are activated and functioning properly; that no interferences exist; and that all configurations necessary to reach those work locations will allow the operator to remain under the fifty percent limit of the hoist's rated capacity. Materials and tools to be used during the actual lift can be loaded in the platform, as provided in subsection (8)(d) and (e) of this section for the trial lift. A single trial lift may be performed at one time for all locations that are to be reached from a single set-up position.
(b) The trial lift shall be repeated prior to hoisting employees whenever the crane or derrick is moved and set up in a new location or returned to a previously used location. Additionally, the trial lift shall be repeated when the lift route is changed unless the operator determines that the route change is not significant (i.e., the route change would not affect the safety of hoisted employees).
(c) After the trial lift, and just prior to hoisting personnel, the platform shall be hoisted a few inches and inspected to ensure that it is secure and properly balanced. Employees shall not be hoisted unless the following conditions are determined to exist:
(i) Hoist ropes shall be free of kinks;
(ii) Multiple part lines shall not be twisted around each other;
(iii) The primary attachment shall be centered over the platform; and
(iv) The hoisting system shall be inspected if the load rope is slack to ensure all ropes are properly stated on drums and in sheaves.
(d) A visual inspection of the crane or derrick, rigging, personnel platform, and the crane or derrick base support or ground shall be conducted by a competent person immediately after the trial lift to determine whether the testing has exposed any defect or produced any adverse effect upon any component or structure.
(e) Any defects found during inspections which create a safety hazard shall be corrected before hoisting personnel.
(f) At each job site, prior to hoisting employees on the personnel platform, and after any repair or modification, the platform and rigging shall be prooftested to one hundred twenty-five percent of the platform's rated capacity by holding it in a suspended position for five minutes with the test load evenly distributed on the platform (this may be done concurrently with the trial lift). After prooftesting, a competent person shall inspect the platform and rigging. Any deficiencies found shall be corrected and another prooftest shall be conducted. Personnel hoisting shall not be conducted until the prooftesting requirements are satisfied.
(g) The employer shall retain at the jobsite and produce when requested, documentation such as lift capacity information, verifying that the requirements of this standard have been met.
(10) Work practices.
(a) Employees shall keep all parts of the body inside the platform during raising, lowering, and positioning. This provision does not apply to an occupant of the platform performing the duties of a signal person.
(b) Before employees exit or enter a hoisted personnel platform that is not landed, the platform shall be secured to the structure where the work is to be performed, unless securing to the structure creates an unsafe situation.
(c) Tag lines shall be used unless their use creates an unsafe condition.
(d) The crane or derrick operator shall remain at the controls at all times when the crane engine is running and the platform is occupied.
(e) Hoisting of employees shall be promptly discontinued upon indication of any dangerous weather conditions or other impending danger.
(f) Employees being hoisted shall remain in continuous sight of and in direct communication with the operator or signal person. In those situations where direct visual contact with the operator is not possible, and the use of a signal person would create a greater hazard for that person, direct communication alone such as by radio may be used.
(g) Hand signals to the operator shall be in accordance with those prescribed by the applicable ANSI standard for the type of crane or lift in use unless voice communication equipment is utilized. Signals shall be discernable or audible at all times.
(h) Except over water, employees occupying the personnel platform shall use a body belt/harness system with lanyard appropriately attached to the lower load block or overhaul ball, or to a structural member within the personnel platform capable of supporting a fall impact for employees using the anchorage.
(i) No lifts shall be made on another of the crane's or derrick's load lines while personnel are suspended on a platform.
(11) Traveling.
(a) Hoisting of employees while the crane is traveling is prohibited except for portal, tower and locomotive cranes, or where the employer demonstrates that there is no less hazardous way to perform the work.
(b) Under any circumstances where a crane would travel while hoisting personnel, the employer shall implement the following procedures to safeguard employees:
(i) Crane travel shall be restricted to a fixed track or runway;
(ii) Travel shall be limited to the load radius of the boom used during the lift; and
(iii) The boom must be parallel to the direction of travel.
(c) A complete trial run shall be performed to test the route of travel before employees are allowed to occupy the platform. This trial run can be performed at the same time as the trial lift required by subsection (9)(a) of this section which tests the route of the lift.
(d) If travel is done with a rubber tired-carrier, the condition and air pressure of the tires shall be checked. The chart capacity for lifts on rubber shall be used for application of the fifty percent reduction of rated capacity. Notwithstanding subsection (4)(i) of this section, outriggers may be partially retracted as necessary for travel.
(12) Prelift meeting.
(a) A meeting attended by the crane or derrick operator, signal person(s) (if necessary for the lift), employee(s) to be lifted, and the person responsible for the task to be performed shall be held to review the appropriate requirements of this section and the procedures to be followed.
(b) This meeting shall be held prior to the trial lift at each new location, and shall be repeated for any employees newly assigned to the operation.
[Statutory Authority: RCW 49.17.010, [49.17].040, and [49.17].050. WSR 00-08-078, § 296-24-23533, filed 4/4/00, effective 7/1/00. Statutory Authority: Chapter 49.17 RCW. WSR 96-09-030, § 296-24-23533, filed 4/10/96, effective 6/1/96; WSR 91-03-044 (Order 90-18), § 296-24-23533, filed 1/10/91, effective 2/12/91.]