Hazardous Area Rating of Security surveillance cameras
Hazardous Area Rating of Security surveillance cameras
(OP)
As per existing design, lighting & small power and telecom installation along perimeter fence of our facility are non-EX-certified. Perimeter cameras need to be on all the time and no isolation of power supplies to the cameras would be acceptable by plant PSD system upon gas detection from security point of view. All of the cameras are located in non-hazardous area as per existing Hazardous Area Drawings. However, some of them are located closer than others to boundary of some Zone 2 Areas.
What is the best way forward? Is there a consistent approach in the industry? Shall we only EX rate those downwind of potential leak sources? Or only those located close to Zone 2 boundary? Also, what does "close" mean in this case?
What is the best way forward? Is there a consistent approach in the industry? Shall we only EX rate those downwind of potential leak sources? Or only those located close to Zone 2 boundary? Also, what does "close" mean in this case?





RE: Hazardous Area Rating of Security surveillance cameras
RE: Hazardous Area Rating of Security surveillance cameras
RE: Hazardous Area Rating of Security surveillance cameras
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Hazardous Area Rating of Security surveillance cameras
If the boundaries are drawn according to the standard (with the interpretation of a licensed engineer who is experienced with classifying areas), IRStuff's answer applies. Inside the zone, make it suitable for the zone. Outside the zone, it's not a problem.
Don't get concerned with what's downwind or upwind. The wind doesn't always blow the same way!
Good on ya,
Goober Dave
RE: Hazardous Area Rating of Security surveillance cameras
However once you start doing actual consequence modelling of gas release from a sample of sources close to surveillance cameras the result shows that gas at LEL can reach the camera. So the standard itself is very generically optimistic I must admit.
I am looking for the "golden balance" here between API and actual consequences. Depending on what the views are here, we might end up doing consequence modelling for each camera (or for each downdind camera)...
About wind: well, we do base some of our stuff on predominant wind direction (which is 70% from NE at our facility) and rather than making all of the cameras EX (worst case this migh end up with) we can just make those which are downwind because it is veyr unlikely that a gas release occurs with simultaneous "bad" wind direction. So far gas releases at our facility have been very rare events.
RE: Hazardous Area Rating of Security surveillance cameras
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Hazardous Area Rating of Security surveillance cameras
RE: Hazardous Area Rating of Security surveillance cameras
Why did you, er, go to sea, in the first place?
Mike Halloran
Pembroke Pines, FL, USA
RE: Hazardous Area Rating of Security surveillance cameras
Once that's done, you have a clear case for requiring modifications to the cameras that are now inside of the safety boundaries.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Hazardous Area Rating of Security surveillance cameras
However, if you plotted on your demarcated hazardous plans and elevation drawings that your perimeter camera is located outside or falls within the unclassified area, then provide and install a camera with weatherproof enclosure suitable for your specific outdoor environment.
The perimeter camera which are propose to be installed near the Zone 2 areas and those within downwind of potential leak sources are not required to be provided with explosionproof enclosure as it is not mandated in the industry codes and standards, i.e. NEC, API-RP, NFPA 497.
Regards,
Bilegan
Murphy's Law - If anything can go wrong..it will.