Respiratory Protection
With the ever increasing demands for safety and health in the workplace, it is imperative that time is spent evaluating the protection offered when airborne contaminant is apparent.
The selection of respiratory protection follows a basic four-step method
- Identify the hazards – dust, metal fume, gas, vapour.
- Quantify the hazards – measure the hazard level.
- Select the appropriate respirator – disposable, half mask, full-face, powered, airline.
- Training users in fitting and use – to optimise respiratory protection.
Anderco Safety can provide full on-site training and assistance in implementing a respiratory protection program, tailored to your specific requirements.
Identifying the Hazards
Dusts – produced when solid materials are broken down into finer particles. The longer the dust remains in the air the easier it is to inhale.
Mists – tiny liquid droplets formed by atomisation and condensation processes, such as spraying. Mists are often combinations of several hazardous ingredients.
Metal Fumes – occur when metals are vaporised under high heat. The vapour is cooled quickly and condenses into very fine particles that float in the air.
Gases – airborne at room temperature. Able to diffuse or spread freely, gases can travel very far, and quickly.
Vapours – gaseous state of substances that are liquids or solids at room temperature. Vapours are formed when substances evaporate.
Types of Protectors Available
Each type of Respiratory Protective Equipment (RPE) has specific limitations which dictate the types of application for which it may be used. RPE is tested to relevant European Standards which determine the product performance.
Filters
All filters sold within the EU must use the following colour coding system as part of their label.
The service life of a filter will depend on
- Concentration and characteristics of the workplace contaminant
- Filter capacity, i.e. filter class
- Breathing volume and work rate
- Air humidity
- Atmospheric temperature
The lifetime of a gas filter can be roughly calculated by comparing the concentration of workplace contaminant and the minimum breakthrough times permitted for the filter and extrapolating equipment.
Particle filters do not wear-out, they get clogged with particles and moisture. This results in increased breathing resistance. A particle filter must be changed when breathing becomes burdensome.
Occupational Exposure Limits (OEL)
This is a guide to the maximum amount of safe exposure to a substance permissible over a particular period, without suffering any adverse effects. Many large organisations will set their own OEL, however regulatory bodies impose statutory OEL for a number of substances. In Ireland, we can make reference to a guidance document from the UK’s Health and Safety Executive – EH40. This guide is updated annually and revised as further studies are conducted and new information comes to light.
Maximum Exposure Limits (MEL)
Exposure should be reduced as far below the MEL as is reasonably practicable and should not exceed the MEL when averaged over the specified reference period.
OEL Reference Periods
There are two reference periods for which OELs may be set: 8 hour Time Weighted Average (TWA) and 15 minute Short Term Exposure Limit (STEL). A substance may be assigned OELs for either one or both reference periods.
8 hour TWA – some adverse health effects can occur after prolonged or accumulated exposure. The 8 hour TWA is set to restrict the total intake by inhalation over one or more shifts.
15 minute STEL – some adverse health effects may be seen after short exposures. 15 minute STEL may be applied to control these effects. For a substance assigned a 15 minute STEL MEL, this level of exposure should never be exceeded.
Immediately Dangerous to Life or Health (IDLH)
The IDLH concentration of a substance is defined as “exposure is likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment”. The IDLH value represents a maximum concentration from which a worker would escape within 30 minutes without any harmful symptoms or irreversible health effects.
Odour Threshold
The concentration of a substance at which the majority of individuals can smell or taste it.
Protection Factors
This is the method by which we can quantify the effectiveness of a particular respiratory protective device. The Nominal Protection Factor (NPF) is derived from the performance categories of the European Standards to which all respirators are tested.
A Guide to Occuptional Exposure Limits (OEL)
The measured airborne concentration of a respiratory hazard is established by workplace monitoring. The value must be compared to a reference figure to determine whether actions are required to reduce exposure. The reference figure is usually the relevant Occupational Exposure Limit. If the respiratory hazard is above the OEL, various control measures should be considered.
Example
If products containing the solvent Toluene are in use, the exposure to Toluene vapour would need to be established by monitoring.
Toluene is listed in EH 40 with an Occupational Exposure Limit of 50ppm (parts per million).
If the measured level at the workplace were to be above 50ppm, a control measure would need to be implemented to adequately reduce the exposure to Toluene vapour.
The control measures could include improving general ventilation, extraction systems and respiratory protective equipment.
RPE Selection Calculation
Air monitoring is required to measure the respiratory hazard level in the workplace. The hazard level is then compared to the Occupational Exposure Limit (OEL) to determine the required respirator performance.
Example
Wood working
- Measured Respiratory Hazard Level (wood dust) = 70mg/m²
- Occupational Exposure Limit (OEL) = 5mg/m³
Divide the MRH by the OEL 70/5 = 14xOEL.
Respiratory Hazard level = 14 times OEL.
Assuming all other control measures have been considered, select a respirator with an NPF greater than 14 x OEL. E.g. Respair 3V – EN149 2001 FFP3 – NPF: 20 x OEL.
Accessories
There is a wide range of accessories and spare parts available including, for example, specialised carrying cases, sanitising tissues, decontamination covers for blower units etc. For full details on available accessories consult the product user manual supplied with the item or telephone Anderco’s Technical Helpdesk on 1850 303 304.
Care & Maintenance
The requirements of a care and maintenance program vary depending on the type of equipment you purchase. Details will be clearly specified with the accompanying instructions. Most devices will follow a procedure which will include a pre-use visual inspection and, possibly, a fit-test or, in the case of a supplied air unit, a flow check to ensure the appropriate amount of air is being delivered. The procedure may include cleaning and disinfecting. A regular maintenance program monitored by a competent person should be in place and include leak and performance checks, replacement of appropriate parts, such as exhalation valves, and a service history should be maintained.
Corporate Identification
The respiratory product range does not normally have a requirement for end user branding and, consequently, there is little available. Customised carrying cases/storage units may be supplied. Disposable respirators may be branded, however this is dependent on significant minimum order quantities.
