During the risk assessment process for entry into a confined space, the atmosphere must always be taken into consideration. Where it is found that the atmosphere is “safe” the tasks to be carried out within the space may introduce an atmospheric hazard which must be accounted for. Even cleaning and inspection tasks can cause dust to become airborne and a basic dust mask will be required.
The different types of masks and levels of protection are manyfold and expert advice must be sought prior to selection. All users of respiratory protection must have a “face fit test” of the device they are expected to use. This will ensure a good seal to the face and confirm the outside atmosphere does not “bypass” the filtering protection or cause leaks in the case of supplied air systems.
Dust masks for use where airborne particles may be ingested or breathed into the lungs. If the airborne dust is particularly dangerous, asbestos or silica for example a more suitable form of face mask will be required.
Half face respiratory protection, these may provide protection from volatile organic compounds (VOC) dust and other specified airborne hazards.
Full face respirator mask provides protection against airborne particles and protection against particles and contaminants being absorbed by the eyes and tear ducts.
Air fed and powered respirators, this type of protection will provide breathable air from the surrounding atmosphere that is filtered before being blown into a full face mask. This type of device is commonly used by workers using spray systems.
When working in a confined space where there is a danger of oxygen depletion or exposure to another harmful gas, in an otherwise safe atmosphere, the worker may require an escape set. These can come in the form of a compressed air cylinder with up to 15 minutes of escape time or a rebreather system that works on the user “Rebreathing” their own air after the exhaled air has been passed through a “Scrubber” which removes the CO2 from the exhaled air. Rebreather escape sets are more commonly found in underground scenarios, mines for example.
Once the Oxygen concentration in the surrounding air begins to be depleted then a supplied air system will be required. Supplied air systems will come in the form of Self Contained Breathing Apparatus (SCBA) and line fed systems. SCBA units come in different cylinder sizes, different cylinder construction ( Carbon fibre, Aluminium or steel) and durations depending on the task. Line fed systems will be either fed by a compressor or “bank” of cylinders outside the work area
Whichever system is chosen the user MUST receive the appropriate training in how to use the equipment, their life depends on it.