Document ID: chunk:federal_register_of_legislation:F2016L00405:body:0:p21
Version: federal_register_of_legislation:F2016L00405
Segment Type: other
Provision Reference: 
Character Range: 53117–56076

of welding fume).
Where dilution ventilation is used, air needs to be introduced in a way that will ensure effective circulation throughout the confined space, taking account of the configuration of the space, the position of the openings and the properties of the contaminants.
During operations likely to generate contaminants, mechanical ventilation equipment may not be adequate or sufficiently reliable to maintain contaminants at acceptable levels or to ensure a safe oxygen level. Where mechanical ventilation equipment is likely to be necessary to maintain acceptable contaminant levels in a confined space, the equipment should:
    * be monitored to ensure continuous operation while the confined space is occupied
    * have the controls (including any remote power supply) clearly identified, tagged and protected to guard against unauthorised interference.

Flammable gases and vapours

Regulation 72: A  person conducting a business or undertaking must, while work is being carried out in a confined space, ensure that the concentration any flammable gas, vapour or mist in the atmosphere of the space is less than 5% of its LEL, so far as is reasonably practicable.
If it is not reasonably practicable, and the concentration of any flammable gas, vapour or mist in the atmosphere of the confined space:
    * is equal to or greater than 5% but less than 10% of its LEL—the person must ensure that any worker is immediately removed from the space unless a suitably calibrated, continuous-monitoring flammable gas detector is used in the space; or
    * is equal to or greater than 10% of its LEL—the person must ensure that any worker is immediately removed from the space.
Where a flammable atmosphere may exist in a confined space and there is a risk of fire and explosion, all ignition sources in the vicinity must be eliminated.

Examples of potential ignition sources, both inside and outside the space, include:
    * open flames and hot surfaces
    * electrical equipment
    * internal combustion engines
    * metal tools striking metal surfaces
    * spark-producing equipment for example grinding wheels
    * static electricity.

Respiratory protective equipment
If it is not reasonably practicable to ensure the confined space contains a safe oxygen level,
or safe levels of airborne contaminants, then appropriate respiratory protective equipment must be provided. The respiratory protective equipment should be provided and worn in situations where there is no exposure standard for a substance, or where the substance is present in an unknown concentration.
Respiratory protective equipment refers to a range of breathing equipment, including air-supplied and self-contained breathing apparatus. The appropriate respiratory protective equipment should be based on the level and type of contaminants and the work to be done. Whenever there is any doubt about the type of respiratory protective equipment required,
a conservative