(161b) Safety Issues with Installing Pilot Plants in Hoods and Ventilated Enclosures

Installing pilot plants in hoods or ventilated enclosures is becoming increasingly common. Micro pilot plants are placed in laboratory hoods to allow use of contiguous general purpose space, an air conditioned environment, and use the higher ventilation rates for safety and often reducing the area electrical classification. Larger pilot plants are often installed in large floor mounted hoods or ventilated enclosures in open bays to capture any emissions or leaks and, more commonly, to reduce the area electrical classification of the surrounding area and even the area inside as well.

For this to be an effective safety measure, it is critical that one understands, evaluates, and mitigates the issues that arise in operating pilot plants safely in hoods. This presentation will address the major areas of concern including:

• Blocked exhaust air flow due to overcrowding, large solid objects, and similar obstacles to good ventilation
• The limits of ventilation dilution as an effective mitigative measure
• Poor hood construction which often leads to poor air distribution and hence inadequate ventilation
• The problems of pressurized releases
• Poor operating practices including operations too close to the front of the hood, opening too many hood doors, and excessive open transfers
• Design issues including starved hoods leading to reduced ventilation effectiveness, inadequate hood design, and lack of consideration of the effect of penetrations and gaps

The presentation will discuss the issue and suggest some obvious remedies. More importantly it will try and raise an organization’s awareness of the issues so that they may be adequately addressed as part of its hazard analysis and risk assessment.