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Permeable suits are most comfortable for long term wear. Woven garments retain contamination, minimizing resuspension. For more severe conditions, impermeable suits made of rubber or plastic coated or non-woven fabrics are available. Products vary in durability, in their resistance to chemicals, flames and heat, in comfort, in cost, and so on. They also tend to cause and retain perspiration. Some products are more comfortable and flexible, although they may have lower protection factors. Suits are ventilated through sleeves, seams, valves, filters or sometimes several small holes, possibly concealed.
Fully encapsulating, impermeable, pressurized suits (see Section 28) provide the highest level of protection.
The suits can be decontaminated before removal, if this is practicable without further hazard, to avoid transferring or resuspending contamination when removing them. Alternatively, they might be sprayed with a fixative, removed and retained inside a designated area pending specialist decontamination.
Seams in particular should be checked carefully to ensure that they are decontaminated. Minor damage to suits should be repaired, as appropriate, in accordance with the manufacturer’s instructions.
Industrial suits protect against radioactive contamination.
Industrial suits are available in different materials and styles. Permeable suits are most comfortable; impermeable suits are used in more severe conditions. Suits are monitored and decontaminated as necessary.
12. GUIDE FOR CHOOSING PROTECTIVE SUITSProtective clothing normally displays or is labelled with a trademark or other means of identifying the manufacturer, the product type and the intended purpose. The latter may be in the form of a pictogram or symbol with an indication of the suit’s intended level of performance. Manufacturers also typically supply information relating to the care and use of the PPE, and may be willing to discuss the tests applied and performance data. A list of performance levels, preferably in a table of performance, helps in choosing the most appropriate suit for the intended work. Table I is not specific to any particular manufacturer or recognized standard, and is intended only as general guidance for choosing protective suits.
TABLE I. PERFORMANCE LEVELS
Notes ✓ = Type of garment is suitable.
+R = Use together with appropriate RPE depending on specific conditions.
Type C = Air escapes freely through sleeves and seams.
Type D = Exhaust devices such as valves or filters are fitted; pressurized.
Industrial suits of different types provide varying degrees of protection.
Type A suits are unventilated and are made of permeable fabric or of non-woven material. Type B suits are unventilated but impermeable. Types C and D suits are ventilated and impermeable.
Protective gloves range from lightweight disposable polythene gloves to gloves made of other synthetic materials, various fabrics and elastomers, leather, mineral fibres, glass fibre and so on, or from a mixture of materials.
They may be available in different sizes or as stretch to fit; as long gauntlets extending above the elbows or small handpads and mitts covering just the fingers and thumbs; or as separate items, or a fixed or detachable part of a protective suit.
Gloves should be selected to provide the necessary protection while allowing sufficient dexterity. A lightweight polyvinyl chloride (PVC) or thin natural rubber latex (NRL) surgeon’s glove may be suitable for laboratory use where maximum sensitivity and flexibility and a good grip are necessary for accurate work. Heavyweight PVC gloves are more appropriate in a harsh industrial environment. They need to form a barrier against contamination as well as protect against any other harmful agents present such as solvents, chemicals, physical hazards and severe climate. Some users of NRL products suffer allergic reaction after contact with either the glove or the glove powder.
Symptoms may range from localized skin and eye irritations to asthmatic reactions and, in extreme cases, systemic shock. Using a different powder or cream or wearing gloves of a different material under the protective gloves can help.
Elasticated sleeves pulled down over the gloves or tape around the cuffs prevent the wrists from being exposed to contamination. Gloves that become contaminated or damaged should be discarded. This is not feasible when the glove is an integral part of a suit, which is an advantage for gloves that mechanically lock onto the suit. Gloves that are not disposable may need to be properly decontaminated in special facilities.
Gloves of different types for protection against radioactive contamination.
Gloves are likely to become contaminated more easily than other protective clothing. Procedures should be practised to deal with problems that can arise without spreading the contamination to unaffected surfaces or areas.
Contamination may not be easily removable from the gloves, but having paper tissues or paper towels ready to hand will enable tools, monitoring instruments, gas and power controls, handles, communication aids and other essential items to be manipulated through the clean paper.
At an appropriate time and place, gloves should be removed without allowing the contaminated external surfaces of the gloves to make contact with an unprotected hand. This is normally achieved by gripping the outside of the cuff of one glove and pulling the glove inside out but without fully removing it. The fingers inside the turned out glove can then grip the other glove and pull it inside out and off. The partially removed glove is then fully removed turning it fully inside out. The contamination is safely contained on the inside of the turned out gloves.
Procedure for removing contaminated lightweight gloves.
Gloves are the most likely form of PPE to become contaminated. Gloves are removed by a special technique to avoid transferring contamination to other surfaces.
Protective footwear includes overshoes, ‘booties’, shoes and boots.
Overshoes allow personal footwear to be worn in areas where there is a risk of a minor spill or drips contaminating the floor. In their simplest form, overshoes are disposable, single size, foot shaped plastic bags with elasticated openings. More expensive and durable but possibly less effective are outsized plastic shoes (C). These do not fully cover the personal footwear and may not provide a tight fit over it, especially over heels. Fabric overshoes (A) with hard soles and booties (B) and fabric overshoes with legging supported at the knee by elastic or drawstrings provide further inexpensive options.
In an industrial environment, where safety shoes (D) or ‘rigger’ boots (E) with steel toecaps are needed, colour coded footwear of the type is often issued for entry to designated areas. Rubber, rather than leather, safety boots (F) may be preferred to facilitate decontamination or to carry out wet work.
Trouser cuffs, preferably elasticated, should be pulled down over the bootleg to complete the protection. Fully encapsulating, impermeable suits (see Section 28) incorporate appropriate footwear.
Fabric overshoes can be decontaminated by allowing a period for radioactive decay and soaking and/or laundering before reuse. Boots and shoes may need deodorizing and hard brushing or grinding to remove impacted contamination.
Footwear of different types provides protection against radioactive contamination.
Overshoes and safety shoes are worn in potentially contaminated areas. Shoes are monitored and cleaned or disposed of as appropriate.
The reason for using protective footwear is primarily to contain any floor or ground contamination within the designated area. In this respect protective footwear differs from other PPE which has a more direct effect in reducing doses to the worker. Ordinary, personal footwear could be worn where there is only a small risk of potential contamination, but the inconvenience of having to decontaminate or confiscate footwear may be unacceptable.
Barrier discipline is imperative to the effectiveness of protective footwear. A physical barrier should be set up between clean areas and the designated ‘dirty’ area. After placing personal footwear in appropriate storage in the clean area, clean overshoes may be donned before stepping over the barrier. On return, after removing other protective garments, the worker approaches and sits on the barrier. The worker removes one overshoe before immediately swinging the shoeless foot over the barrier. The other foot may then be lifted to remove the second overshoe and again swinging the leg over the barrier without the shoeless foot touching the dirty area floor. Dirty overshoes may not leave the dirty area.
Procedure for removing contaminated footwear.
A disciplined shoe change procedure at the barrier is essential to contain contamination in the designated area.
17. TYPES OF RESPIRATORY PROTECTIVE EQUIPMENTThere are two categories of RPE with several subdivisions in each category (see Sections 19–28):
Respirators purify the air by filtering out particulate materials such as (i) dust or low concentrations of gas or vapour. The most common types
(A) filtering face piece respirators;
(B) half mask respirators;
(C) full face mask respirators; and (D) powered respirators fitted with a fan and filter(s) to supply air to a half mask, full face mask, visor, hood or helmet, blouse, half suit or full suit.
Breathing equipment provides clean air or oxygen from an independent, (i)
uncontaminated source. The most common types are:
(A) fresh air hose equipment, (B) constant flow compressed air equipment, and (C) breathing apparatus which includes full face masks and full suits supplied either from compressed air lines or self-contained cylinders of compressed air.
RPE and some other types of PPE can have an assigned protection factor (APF) defined by national standards and referred to in national regulations. In a typical system, RPE is performance tested to determine the inward leakage (IL) as the ratio of the concentration of the test particles inside the RPE (or PPE) to the challenge concentration of test particles in the test chamber. This is expressed as a percentage, the challenge concentration corresponding to 100%. The manufacturer may quote the inverse (100:IL), called the nominal protection factor (NPF), which is the expected ratio of the concentration of contaminant in the ambient atmosphere to the concentration of the contaminant inside the RPE (or PPE).
The effectiveness of a respirator in minimizing inward leakage depends on
(i) the integrity of the face seal (ii) the filtration capability of the selected canister or filter medium (see Section 20).
Changing either or both of these factors can have a significant effect on the degree of protection actually achieved.
Ranges of nominal protection factors for different RPE.
The two main types of respiratory protective equipment (RPE) are (i) respirators and (ii) breathing equipment. Subdivisions of these types of RPE are described in later sections of this manual.
Several types of RPE might have the necessary APF/NPF to conform with the predicted contamination and/or measurements (see Section 7) taken to determine the physical form and concentration of contamination in the workplace.
The choice could include all types of RPE to protect against low concentrations of a particulate contamination. Radioactive vapours and gases would restrict the choice to certain types of respirator or breathing equipment or, for adequate protection against contaminants at high concentrations in the ambient atmosphere, breathing equipment may be the only possibility. Tritium gas has a high diffusivity and necessitates special considerations to prevent its inhalation, ingestion or absorption through the skin.
The APF/NPF indicates the theoretical best protection that can be achieved.