(71b) Using Ventilation to Reduce the Area Electrical Classification of Pilot Plants and Laboratories

Using Ventilation to Reduce The Area Electrical Classification of Pilot Plants and Laboratories

All codes allow the use of ventilation to mitigate against the risk of a fire or explosion from flammable gases and vapors. The use of ventilation to reduce the area electrical classification of pilot plants nd laboratories is a well established practice. However, the risk mitigation is often poorly analyzed and often rests on questionable assumptions. This leads to the potential for inadvertently being at a higher hazard level than the organization realizes.

This presentation will address several issues regarding the effective use of ventilation to reduce the risk and hence allow a lower area electrical classification. Areas to be covered include:

• A brief summary of the code requirements
• A discussion of how ventilation can – and cannot – mitigate fire and explosion hazards
• A discussion of how hoods and ventilated enclosures often fail to contain the results of leakage, spills, and equipment failures including:
  • Inadequate design
  • Too low an exhaust rate
  • Over crowding
  • Poor exhaust distribution
• Some guidance on how to use ventilation effectively
• Guidelines on how to make ventilation effective