Document zd18Vpp4jQeab7pevOan0n8g0

personal protective equipment holes through the shell and shall contain no metal parts, either m the shell, suspension, or accessories General Service and Fireman Service hats or caps are designed to withstand a minimum electrical test voltage of 2,200 volts AC (rms), 60 cps, for one minute with leakage current not in excess of 3 miQiamperes Nonconductive utility service head protectors must withstand an electrical test voltage of 20,000 volts AC (rms), 60 cps, for three minutes, with leakage current not in excess of 9 milliampares When tested to breakdown, they shall not fail below 30,000 volts. Class A, B, and D hats and caps are de signed to transmit a maximum average force of not more than 650 pounds when subjected to a 40 ft-lb impact load For Class C hats and caps, the impact load is 24 ft-lb Nonconducbve hats also are designed to have a burning rate of less than 3 in /nun with an absoipbon rate of less than 0 5 per cent (by wt) of moisture m 24 hr immersion m water When used properly, these hats will greatly reduce exposure to electric bum injuries as well as to falling objects." The American Standard Safety Code 721 (see earlier footnote) specifies the weight for all but Class D hats and caps shall not exceed 15 oz, complete with sus pension but exclusive of winter liner or chin strap The Edison Electric Institute specifi cation AP-1 (see earlier footnote) calls for a minimum weight of 15% oz for nonconductive headgear. A hat with a brim all around provides the most complete protection for the head, face, and bade of the neck For confined spaces where the bnm Is in the way, the cap type is frequently preferred This type may also be equipped with lugs to support the welding mask if a welder works on con struction jobs or in other places which exj?ose him to head injury Metal hats do not afford as high a degree of impact resistance as do plastic hats but because of their lighter weight they are pre ferred by some workers They should never be used where electrical hazards or substances that are corrosive to aluminum are present Class B insulating hard hats and caps should be inspected before each usage for cracks, signs of impact, and rough treat ment Loners are available so that protec tive hats may be worn with comfort in cold weather (Fig 36-3c) At least every 30 days, hard hats (par ticularly the sweatbands and cradles) should be washed in warm soapy water or suitable detergent and then nnsed thoroughly Be fore used hats are reissued to other em ployees, they should be scrubbed and disin fected Formaldehyde, modified phenohes, hypo chlorite, or quaternary ammonium com pounds in proper strength can be used to disinfect hard hats Cleaning and disinfect ing solutions and powders are available which combine both operations Hats should be thoroughly nnsed with dean water and then dned (Rinsing is not necessary when quaternary ammonium compounds are used as their disinfecting properties continue on and they are usually nonrmtating ) Do not use steam or solvents for deaning and dis infecting, except on aluminum hats Many companies make use of colored hard hats to identify different working crews Many colois are available some colors are painted on and others have the color molded m Before painting a hat, consult with its manufacturer so that a coating can be chosen which will not only hist but which will not reduce the dielectric properties or attack and soften the shell material Light er colored hats are cooler to wear in the sun or under infrared energy sources Once broken, the crown of a hard hat cannot be effectively repaired, but the sweatband and cradle can be repaired or easily renewed if worn or badly soiled An adequate number of crowns, sweatbands, and cradles should be stocked as replace ment parts Various types of leather, fabric, and elas tic chinstraps are available Often hats arc "Edison Electric Institute, 750 Thud Ave, New York City Specifications for Electrical Workers Insulating Safety Head gear. AP-1-1961 American Standards Association, op crt 36-5