When it comes to plant safety, personal protective equipment is an essential feature. Crucial among such equipment, reports Sean Ottewell, is the reusable respirator.
Tighter regulations and an increased focus on safety mean that reusable respirators are becoming even more common around the plant. As a result, 3M has issued a guide which shows how to get the best out of them. According to the company, modern products are highly versatile and can be fitted with a variety of filters which reduce the wearer's exposure to gases, vapours and particulates, depending on the filter used.
Checks, care and maintenance
The company says: "However, respirators will only offer the wearer effective protection, with product working life maximised, if pre-use and post-use checks, care and maintenance, and replacement of consumable parts are carried out at the right times and in the correct manner. Appropriate storage for any periods when products are not in use is also crucial."
Unlike single-use respirators, which can usually be assumed to be intact and ready for use on removal from their packaging, a series of checks should be made by the user before they wear a previously used reusable respirator.
To begin with, says 3M, the face piece should be checked for cracks, tears and dirt, while the inhalation valve may also harbour cracks and tears. While washing may be adequate to remove dirt, it goes without saying that any respirator which has any cracks or tears is likely to offer significantly reduced protection, potentially exposing the wearer to hazardous levels of gas or particulates, and should not be used.
The next step is to check that the head straps are intact and have elasticity. Respirators whose straps have lost their elasticity are unlikely to offer a snug enough fit around the user's face, potentially leaving gaps through which harmful gases and particulates can pass.
The user should also check that all gaskets are present and then remove the exhalation valve cover to examine the exhalation valve and seat for dirt, cracking or tearing. Once again, any product displaying either cracks or tears should not be used. For both half-face and full-face masks, a variety of spares are available and employers would be well advised to maintain a stock of spares for each product type used on site to allow any repairs to be undertaken immediately thus avoiding costly employee downtime. The lifetime of lenses can also be prolonged through the use of peel-off lens covers.
Correct filters
Once the user has satisfied himself or herself on all these points, and the correct filters - either gas or particulate - are attached, the product can safely be worn.
"One issue which can significantly impact on the protection offered by reusable respirators is what happens to them when they are removed mid-shift, for example for lunch or a comfort break, and when the user returns and put them on again. Unfortunately, it is not unheard of for the user to remove the product while still in the hazardous area. This is dangerous enough in itself but the problem is exacerbated if the respirator is then left in the area where harmful contamination can settle on the interior of the product, meaning the next time it is worn, the user is breathing potentially highly toxic air. Employees should be instructed, therefore, to always don the respirator before entering the affected area and not to remove it until they are well clear," notes the company.
After use, reusable respirators should be cleaned and, if required, disinfected. The user instructions with the product will contain the cleaning and disinfection requirements. Masks are generally cleaned with a specialist, disposable cleaning wipe or by immersion in a cleaning solution. A soft brush can be used if scrubbing is required. After washing, the product should be rinsed in fresh, warm water and air dried in a non-contaminated atmosphere. Respirators are also sometimes cleaned in a washer.
Once dry, masks should be stored away from contaminants in a clean area, with full face masks stored face-up to reduce the risk of scratches to the lens.
Risk assessment
Given variations in usage levels and also in the quantity of gas and particulates being filtered, it is difficult to be prescriptive about the intervals at which the filters should be changed, although a thorough risk assessment will give some indication. As a rule, particulate filters can be used until the user notices they are becoming harder to breathe through, while gas and vapour filters should be replaced before they become saturated, or as a last resort, when the user notices a smell or taste of gas, which indicates that the carbon contained within the filter is saturated. For this reason gas and vapour filters should be used only to guard against gases and vapours with good warning properties.
When it comes to record-keeping, all reusable respiratory protective equipment (RPE) is subject to the maintenance requirements of the relevant EU legislation, for example the Control of Substances Hazardous to Health regulations (COSHH) in the UK. Records of monthly maintenance and testing must be kept for at least five years and must be able to be produced on demand for a Health & Safety Executive (HSE) inspection.
Record cards are available from a number of sources including respirator manufacturers. A monthly check should be made of the face seal, nose cup, straps, valves and gaskets, and visor, with details noted on the record card.
Maintaining good practice in the area of record-keeping, as well as adopting a strict regime of pre and post-use checking, cleaning, maintenance and storage, will help to ensure that employees remain safe and that legal requirements are satisfied.
In terms of its own latest developments, 3M has launched the 7500 Series reusable respirators. These half masks combine unrivalled levels of wearer comfort with fully replaceable parts for maximum durability and quality. They are available in three sizes, use all of 3M's 2000, 5000 and 6000 series filters, use a 3M Cool Flow valve for easier breathing and reduced heat and moisture build-up, and come with a novel head harness and yoke design for greater stability and more comfort.
New from Scott Health and Safety is the ELSA escape respirator, an emergency breathing device providing five, 10, or 15 minutes of escape from toxic environments. Also available is a high flow five-minute unit with a nominal airflow of 68 l/min which is ideal for escape where breathing rates may be stressed. ELSA is designed for comfort as well as simplicity of use and can be worn by those who wear glasses or have beards. Other benefits include: a rechargeable aluminium cylinder; a pressure gauge on the cylinder valve to verify cylinder pressure at a glance; an elastomeric neck seal allows for easy donning, proper neck fit and repeated usage; clear polyurethane hood provides 360° visibility; and a detachable hood for cleaning.
A related product, the Speed Evac escape respirator is a mouth bit respirator that provides the wearer with a timely escape from toxic non-IDLH levels of ammonia or acid gases including chlorine, chlorine dioxide, sulphur dioxide, hydrogen sulphide or hydrogen chloride. Speed Evac is disposable, requiring no cleaning or maintenance. It is unaffected by facial hair and requires minimal training for use.
The Ska-Pak Plus supplied air respirator features a streamlined profile for entry into or escape from hazardous confined spaces or toxic IDLH situations. An environment resistant nylon harness, or a heat resistant Kevlar harness are options. Also available is a full body fall protection harness. Ska-Pak Plus is offered with a complete range of cylinder types and pressures.
Fan-assisted helmet
Meanwhile, Sundstrom says it is the first manufacturer to launch a fan-assisted helmet with a TH3 class visor. This can be combined with respiratory protection that affords the best possible comfort and the highest level of protection. The SR 580 can also be used together with compressed air attachment SR 507 in environments where there is potential for exposure to contaminants that have poor warning characteristics. The SR 580 provides complete protection when respiration, face and head protection is required. Sundstrom says it can be combined with a majority of ear defenders, while a polycarbonate visor gives a large field of view and is simple to replace.
Also new from Sundstrom is the SR 90-3 half mask, an upgrade of its SR 90-2 model. This mask comes with improved comfort and new exhalation valves which ensure very low exhalation resistance (Fig. 1). The valve covers have partitions that effectively protect the exhalation membrane from dusts and mists. The SR 90-3 is a thermo plastic elastomer mask and comes in sizes, S/M and M/L.