Ventilation and Gas Detection

[bobgorno]

For the partially enclosed issues. re-look at 6.3.2.4.7.

Simplified Div. 2 cirteria: Inadequatley ventilated, with adequate gas detection = Div. 2. See 6.5.1a. Technically non-ventilated space is OK with adequate gas detection, however nuisance trips will cause management to ask you to jumper out the trips, thus adequate gas detection is compromised.

Kent, RE your statment about declassifying to Div. 2 because the equipment didn't meet Div. 1. Be very careful. Classification comes first. Equipment must meet the classification. Do not reverse these. I remember about 15 years ago, a pipeline that shall remain nameless was fined heavily by OSHA for adjusting the classification to meet the equipment.
You probably have problems with ignition systems, coils, and spark plug wiring that are not shileded, Div. 2 approved. Typically I have heard compressor mechanics like to swap out shielded, Div. 2 coils to the non-approved, unshielded types because it's easioer for them to start-up the machines. Not good......


Bottom line, get the gas detection and alarms and shutdowns correct so you can justify Div. 2.

 

[KentAT]

Kent, RE your statment about declassifying to Div. 2 because the equipment didn't meet Div. 1. Be very careful. Classification comes first. Equipment must meet the classification. Do not reverse these. I remember about 15 years ago, a pipeline that shall remain nameless was fined heavily by OSHA for adjusting the classification to meet the equipment.

I might not have been clear. Our company isn't reclassifying from Div 1 to Div 2 because of existing electrical equipment not meeting Div 1. They are saying that in the design of new installations, we had been too conservative in the past by classifying the areas as Div 1 for those areas that upon closer scrutiny and decision making do not meet any of the criteria that require a Div 1 classification. Therefore, these new areas are being classified as Div 2 instead.

As for existing inadequately ventilated installations that were originally classified as Div 1, the position is that if we can eliminate or modify the equipment so that nothing remains that meet the criteria that requires a Div 1 classification, along with gas detection and forced ventilation the area can be reclassified as Div 2.

My concern is that I have seen no policy, method, result, or history as to how any area is judged to NOT have the possibility of simultaneous process equipment failure releasing gas and causing electrical failure that presents a risk of ignition. Ditto that about what is considered as "frequent" as relating to leakage.

I guess it is really my personal problem because too often I see the result of judgement decisions being biased towards the lesser of two evils (in this case Div 1 is seen as the greater "evil" due to increased $$ - I do not entirely share that idea) without being able to show that due diligence was indeed performed.

In keeping with your example, I am pretty confident that should OSHA ask to see how our areas were deemed to not have the "simultaneous risk ..." and not be considered "frequent..." there would be nothing available to show what criteria were studied and how any specific area was judged against that criteria.

I guess I am just ranting on...