How to choose dust respirators
Dust and fumes from grinding and similar jobs raise the question of which type of disposable or re-usable respirators and PPE to use.
Some workers use four disposable dust masks per day. Below are respiration protection principals and advice from a supervisor level toolbox talk, and from Buildsafe SA.
Exposure to respiration risks like dust, particles, dry chemicals, mists, fumes or biological agents, have to be prevented or managed in practical ways. When exposure is unavoidable, employers have to provide effective personal protective equipment (PPE).
Respirators, breathing apparatus, masks, air lines and other breathing personal protective equipment (PPE) types are among the ‘last resorts’ in risk exposure and occupational hygiene management provided for in labour legislation.
The SA Occupational Health and Safety (OHS) Act, under General Safety Regulations, section 2 (2), stipulates that, taking into account the nature of workplace hazards, safety equipment and facilities shall include suitable safety equipment or facilities of a type to effectively prevent bodily injury.
Other General Safety Regulations (GSR) sections, and Regulations under the OHS Act, make specific reference to respiratory equipment according to specific hazards;
• GSR section 5 on Work in Confined Spaces
• GSR section 9 on Welding, Flame-cutting, Soldering and Similar Operations
• Hazardous Biological Agents Regulations, section 11
• Hazardous Chemical Substances Regulations, sections 8 and 11
• Lead Regulations, sections 9 and 12.
Signage in respiratory haz areas
Areas where respiratory equipment are compulsory to wear, must be identified by a mandatory symbolic safety sign of a standardised blue circle with white border, around a white pictogramme of a breathing mask or respirator.
Buy respirators that that have been tested and bear relevant logo marking in terms of South African Bureau of Standards (SABS), South African National Standards (SANS), or European Norms (EN).
Be aware that some brands and some branding may be abusing SABS, SANS or EN marking, so check certification with the supplier and with the certification body.
Ask suppliers to present specialist training sessions on PPE selection and use. Read instructions and pamphlets. Do not share or re-use disposable PPE. Do not tamper with PPE or customise it for use.
If PPE is not giving adequate protection, report it, and ask for medical surveillance of exposed workers.
Selection of respirators
Employers should consider several interrelated workplace aspects before selecting, buying, issuing and managing respiration PPE, including at least these factors;
• Hazard level.
• Type of hazard, pollutant or contaminant.
• Particle size.
• Concentration in the atmosphere.
• Duration of exposure.
• Risk level due to type of work and worker awareness and training.
• Type of work to be performed. Rescue, salvage, routine work or continuous hazard, each contribute to the risk and the most effective equipment to be purchased.
• Level and duration of protection required. This must match to the level of hazard and the type of work to be undertaken. The longer the wearer is in the hazardous area, the more protection is needed.
• User comfort. Size, weight, shape and style should prompt users to want to wear the equipment. Discomfort should be avoided.
• User performance. Users should be able to carry on breathing normally once the equipment has been put on. There should be no need for extra exertion. The apparatus should also be easy to operate and not cause additional stresses.
• Cost effectiveness. Depending on hazard level, number of people who will be wearing the equipment, and type of protection needed, an analysis of various types and providers should be undertaken to determine the best hazard and risk management solution. Buying cheap could become expensive due to factors like longevity, clogging, productivity, user rejection, or health exposure.
Types of respirator PPE
Filter respirators purify the air being breathed by ensuring that inhaled air is drawn through a medium that removes harmful substances
Breathing apparatus provide air or oxygen to a wearer from an uncontaminated source, either by air line, air, or cylinders supplying atmospheric air. Note that pure oxygen is not breathable and lethal. -Source; Advantage ACT Toolbox Talks © 2010.
Protect eyes, hands, skin
A Buildsafe SA circular on respiration protection in construction work, notes that selection of respirators depends on the contaminant type, form, and concentration. Workers must also follow good hygiene practice, like overalls, washing hands, and housekeeping.
Gloves of cloth or leather are recommended for grinding haz materials, unless the grinder type requires that gloves must not be used due the risk of glove material being caught by the grinder wheel.
Against a combination of grinding and dust risks, add eye protection by safety goggles, or face shield over safety glasses.
Where exposure is likely, use protective clothing to prevent contamination of personal clothing. Hearing protection may be required, depending on tools, material, situation, and job duration. Grinding of some materials, or grinding in confined spaces, raise dust noise and dust levels.
Assess dust risks
PPE types and specifications depend on the task. Grinding work must be reviewed in the risk assessment process, and control measures implemented.
Certain materials, like stainless steel, gives off more toxic fumes than mild steel and require a more advanced filter system than a dust mask.
Work in a ventilated area, or blow away and extract fumes generated by grinding, rather and providing PPE as a last resort.
The South African Occupational Health and Safety Act in section 8 (2) (b) requires “taking such steps as may be reasonably practicable to eliminate or mitigate any hazard or potential hazard to the safety or health of employees, before resorting to personal protective equipment.”
Face and head protection combinations
Some work teams use 180 degree vision goggles with the option of full face protection shields, suitable for amateur or professional use. Some head protection kits are also instantly customisable to a variety of jobs, like head, eye, face and hearing protection combinations.
Some goggles have anti-fog coating, good ventilation over the eyes, space for prescription spectacles, secured by a wide, comfortable elastic strap, with detachable face shields that clips on or off. The combination is suitable for long periods of use and for varied tasks.
USA dust exposure guidelines
Material safety data sheet (MSDS) for Vitrified Grinding Wheels, from the USA Exposure Guidelines for Hazardous Component, section 8, offers this calculation of respirable components in total dust;
Aluminum Oxide OSHA PEL 15 mg/m3 total dust; ACGIH TLV 1 mg/m3 respirable Al metal
Silicon Carbide OSHA PEL 15 mg/m3 total dust; ACGIH TLV 10 mg/m3 inhalable fraction
Workers, supervisors and buyers of personal protective equipment (PPE) must consider components of materials and coatings being worked on site.
General ventilation must be used, and local ventilation could be added to minimise exposure and to maintain the concentration of contaminants below the TLVs.
USA workers use NIOSH approved respirators if exposure limits have to be exceeded, or where dust exposures are excessive.
USA OSHA has specific standards for lead, cadmium, and other hazardous materials dust, including OSHA 1910.134. -Source; Buildsafe SA RFI 021.
PHOTO; A worker wearing a respirator, eye protection and overall, preparing for a grinding job.
Edmond Furter
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