RECOMMENDED SPECIFICATIONS FOR SHORT AND MEDIUM LENGTH LADDERS
Good Practice Requirements Suggested by the Ohio Inspection Bureau, and the West Virginia Inspection Bureau
LADDERS for Fire Department use necessarily must be of better material and workmanship than those for ordinary purposes. They should be especially built for Fire Department service and no attempt made to merely adapt commercial ladders to this use. In addition to the standards set forth in the code of the American Standards Association, the following specifications are recommended by the Ohio Inspection Bureau and the West Virginia Inspection Bureau:
These specifications in general should be considered as pertaining to ladders less than 35 feet in length; those that do not have poles or other special construction; or those that usually can be raised by two men or less. The three general types of ladders commonly used and considered here are: (1) Roof, hook, or scaling ladders: (2) Wall, single or straight ladders; (3) Extension ladders.
BEAMS OR RAILS: These shall be of straight-grained wood, free from objectionable defects. This wood shall be carefully selected and thoroughly seasoned. Douglas fir, also known as Oregon red cedar, should preferably be used. Pieces should be smooth, free from splinters and with corners slightly rounded.
RUNGS: These shall be of straightgrained second growth hickory or ash, firmly secured to the beams or rails.
CROSS OR BRACE RODS: These shall be of steel, bolted. There shall be one near each end rung, and spacing shall not exceed 5 feet.
HARDWARE: All hardware shall be of rust-resisting metal, or thoroughly plated or painted. All bolt heads and nuts shall be of a type that will protrude as little as possible, so as to avoid catching on window ledges, cornices, eaves, etc.
HEELL IRONS OR SPURS: All ladders shall have heel irons with double nibs extending at least 3/4-inch. On wall, single or straight ladders heel irons shall be placed on all four beam ends.
HOOKS: Collapsible hooks of roof or sealing ladders shall be of ample strength and sturdy construction. They should be of the long-sweep type, so as to make them useful over window sills and parapets. In general, hooks should curve from the inside of one rail to near the inside of other. In all cases the hooks shall be so placed that the beam ends will protrude as far as the rounded part of the hooks, thus making the ladder equally useful as a wall ladder. Also in all cases the hooks shall be firmly and adequately fastened to the ends of the rails. The latter should preferably be banded.
LOCKS, DOGS, LATCHES OR PAWLS: These shall be of sturdy construction and positive in their action. The nibs or hooks shall be plated or painted traffic yellow, white, or some color to aid visibility in smoke or darkness.
PULLEYS: These shall lie of plated steel, bronze or equivalent metal, selflubrlcatlng, of good diameter and with ample rope groove.
ROPES OR HALYARDS: All ropes shall be of a good grade manilla, preferably treated, not loss than 3/8-inch. A harness snap should not be placed on the hoisting rope, although this or some equally quick fastening device is desirable on the lower end of rope.
EXTENSION LADDERS carried on pumpers or hose trucks shall be not less than 24 feet. The length shall be considered as the practical working length when allowing for a safe overlap. A stop or catch should be provided to Insure against overrunning the safe overlap. All movable parts shall operate freely, without binding or undue play.
PAINTING: The beams and rungs shall not be painted, except near the ends of the ladder. A good grade of filler end of Clear spar varnish may be used on the beams and rungs. The top 18-inch of all beams and the top rung shall be painted some distinctive color to aid visibility in smoke and darkness. Traffic orange-yellow, pure white, or alternate diagonal black and white stripes can be used. Cadmium-plated hardware may be used in place of the foregoing. The bottom of ladders should be painted black, except that the bottom rung may have alternate stripes if desired. On so-called double-end ladders the “top’ is determined by position of brace rods. The working length shall be plainly painted on at least two places on each ladder, with contrasting numerals at least 1 1/2-inch high.
MOUNTING BRACKETS AND VESTING: These shall be of a type that will hold the ladders rigid while in transit and not allow chafing. They should preferably be leather-lined. (Brass plates used at contact points, have a tendency to work loose and injure men’s hands.) Where a roof ladder and an extension are nested and carried together on the side of a truck, the mounting should be such that the outside ladder can be taken off separately and easily. In other words, it should not require two men to unload the three sections since either ladder usually can be handled by one man after it is off the truck. On pumper or hose trucks the collapsible hooks of roof ladders should be carried toward the front on ladder trucks, where ladders are mounted flat, the hooks should be toward the rear.
WIDTH of sections should be such that where the combination of a roof ladder and an extension are furnished for a pumper or hose truck, the roof ladder will nest or fit entirely inside the fly ladder and not be the same width, as so frequently constructed in the past. The modern arrangement allows the gaining of additional height in extreme emergency by readily lashing, or otherwise fastening, the roof ladder to the fly ladder.
TESTS AND LOADING: Every ladder shall be capable of easily withstanding the following tests without undue sag or strain, when set at a good working angle:
A dead weight or load of one man’s weight (200 lbs.) every 5 feet or a live or moving load of 200 lbs. every 10 feet.
Each rung, when tested senarately a dead weight at center of 400 Ibs.