Document 37pBXkdRD1pBZpek3zDZO7BdO

1957 National Safety Congress Pounced a sew -13 mask for troops. It is designed to give the soldier complete protection against the inhalation of scar gases, germ warfare agents and airborne radioactive fallout particles, but does sot protect against direct radiation. The new mask does not have the pro truding canister used in current masks. This seas made possible through develop ment by the Chemical Corps of a new light-weight pliable gas-aerosol filter ma terial. Pads of this material are enclosed within cavities molded into the robber face piece of the mask. Lower breathing re sistance, superior vision, better speeth trans mission, and greater comfort are claimed. It should be noted that the CD V-800, the existing and the new Army gas masks should be used for purposes for which they were designed only. After both World War I and Tt several instances were reported where ``surplus* Army masks were used for protection against gases for which they were not designed, with serious conse quences. It Is important that gas masks are not misused. B. AJR-SUPPUED RESPIRATORS gmre the simplest solution to all respira tory problems is to supply pure air to the brother, the use of an air supply from some remote source where the air is not contaminated is both simple and logical For many applications, air-supplied equip ment has real advantages, but this equip ment is subject to definite limitations. The simplest type is the Bureau of Mines Type B hose mask, which is a facepiece to which is attached a hose without a blower which must extend to a respirable source of air. This mask depends on the breathing action of the wearer to move the air. For this reason, a Twa^-iynum hose length of /a feet been established for the hose mask with out blower. Low pressure Mowers, operated either by temrl or by power (power blowers do not carry Bureau of Mines approval) are used to supply Bureau of Mines Type A hose casks up to 150 feet All hoses should originate at the blower. A respirable source of air must be as sured, and a safety man must be present d tin; blower at all times. Fouling of the hose may art off the air supply, and the ^ptt route must be the same as the entrance route. These hose masks can be used safely only if the above precautions are observed. Afrlme-snppUed Bureau of Mines Type C respirators are divided into two classes: (a) the continuous flow type and (b) A* demand or intermittent demand flow type; (a) is usually used with a powered compressor or blower, while (b) is usually used with breathing air supplied from cylinders. The use of such equipment in atmospheres im mediately hazardous to life is not recom mended <twr failure of the air supply or fooling of the hose would be serious, and further, it is absolutely necessary to have respirable air of unquestioned quality. We have previously noted the hazard of using a jdarit air supply for air-supplied breathing equipment. It is recommended that a separate air system be used exclu sively for breathing air. Depending on the pressure available and the diameter of the hose, there is a limit to the length of hose which is practical Wherever possible, such systems should be piped as close to the outlet as possible so possibility of fouling of the hose and cutting off the air supply will be minimized. Exit from areas where air-line respirators are used mnst, of course, be the same as the route in. If a compressor or tank sup ply is sufficient pressure relief control must be available to protect the wearer apma pressure in excess of that prescribed for the equipment AlfUNRATH) SUnS Air helmets, air books, and air-supplied suit; hare the same general limitations as for air-line respirators. An interesting de velopment in this field is the use of airinflated suits for protection of the whole body against hazardous materials. To form, the large impervious plastic tunnel or pipe allows a man to work in one room while using air from another-- the slight air pressure supplied giving both breathing air and inflation (or body) to the suit The front of the suit is tailored into a facepiece, and arms with gloves are at tached. Mobility is reported good within the obvious limits imposed by the length of the vwim#! attached. In another form, a complete suit with buflt-m arms and legs is supplied with air for inflation and a hood, also air supplied, 18 Chemical Industries is used for head, face and respiratory* pro tection. Depending on the particular fabric, plastic, or composition used in its construc tion, this suit allows work inside tanks, reaction vessels and other confined space which still contain a hazardous atmosphere. Properly used, together with safeguards to insure that the wearer's air supply and life line are always in proper position and work ing order, this suit has increased safety and decreased operating costs in maintenance work inside tanks containing materials which are corrosive or are easily absorbed through the skin such as aromatic ammo and nitro compounds. The same limitations noted above for air-line respirators should be noted. Regardless of the type "respirator" used, a definite program of control is nccessarv to insure the device is used properly, is prop erly maintained, and that it is doing what is expected of it After the CkJk River atomic reactor incident, respirators were used to prevent inhalation of radio active contaminants. This program was suc cessful only after a respirator official was appointed to control the use and mainte nance of respirators, regular urine-samples were analyzed to show definitely the degree of absorption, and an improved respirator was made available. C SELF-COSTAIKED BREATHING APPARATUS Self-contained breathing apparatus supply complete respiratory protection in any con centration of toxic gases and under any oxygen deficient atmosphere. However, cer tain gases and vapor will cause systemic poisoning by skin absorption. Although a small group, these exceptions are highly important, including hydrogen cyanide, nitro and amino aromatic compounds, ethylene inline, phenols and a few others. These gases and vapors require complete skin protection of an impervious type in addi tion to respiratory* protection. EARLY RBREATH1NG APPARATUS The early self-contained rebreathing ap paratus, which was imported from Europe, had serious deficiencies. Loss of life was reported by users in this country; 19 acci dents are reported involving 26 facilities between 1911 and 1940, due partly to equip ment failure and partly to improper use. IVhere life-lines and standby rescue squads were employed, the apparatus was generally satisfactory in the hands of well-trained users. The first self-contained breathing appa ratus to be approved by the U. S. Bureau of Mines was of the two-hour rebreathing type. The oxygen rebreathing type apparatus is relatively heavy (39# for the two-hour type) and is bulky. Most self-contained (dosed circuit) oxygen breathing appara tus in use today require mouth breathing with a nose dip, but a full facepiece has recently been approved. Careful training is required in use and in maintenance of this apparatus. A minimum of 20 hours initial training is recomnusided by the Bu reau of Mines. RESTRICTS MOVEMENT Demand-type air and demand-type oxygen breathing apparatus is available in half-hour, quarter-hour and 7)6 nunute ratings. Only the half-hour demand apparatus is Bureau of Mines approved; the Bureau has no approval schedule at present for any selfcontained apparatus of less than a half-hour. Although the schedule of work on which the Bureau's half-hour rating is exhaust ing. large men under enymif stress have exhausted a half-hour (40 cu. ft.) cylinder in significantly less than a half-hour. Differing only in whether it is supplied with compressed oxygen or compressed air, the apparatus weighs nearly 30 pounds for the half-hour type, with the large cylinder (40 cubic feet) on the back. It is relatively awkward to put on and it restricts action in confined spaces. With practice, it may be put an and into operation from a mounted backboard in less than 20 The bad; position of the cylinder makes H difficult to craw] under equipment. Climb ing in and out of small openings, such as manholes, requires care when wearing this type apparatus. Operation of a motor ve hicle is awkward when wearing a cylinder on the back. (15-minute and 7j-mimite donand apparatus use gmallw* cylinders slung on the side of the wearer, which overcomes this objection to some extent.) The purity of the air or oxygen with which the cylinder has been charged should always be questioned since other gases such 19