Originally posted by sirdle:
tariqalauddin,
The real questions here, are: Is it dangerous to drive a car through a Class 1, Div II area? and should you, as a safety professional, be concerned?
?Class? is designated by Roman numerals (I, II, III) and Division by Arabic (1, 2)
The answer to both of these questions is YES!
I stand by my previous reply. If you?re worried, consult with your insurer ? they probably won?t be concerned.
While the NEC does not directly address the question of automobiles in classified areas, it does provide basic information which can be used to understand the nature of this danger.
The NEC is an equipment installation standard and the ?basic information? supplied is insufficient to determine the dangers. One must refer to another document such as NFPA 497 or API RP 500
A Class 1, Div II area is one in which combustible gasses MAY exist in sufficient concentrations such that a source of ignition could cause the gas ignite. BUT, it is understood that this is not a normal process condition... an abnormal condition or
an accident would be required for this gas to be released.
This part is not accurate. Both NFPA 497 and API RP 500 recognize accidents are not a basis for electrical area classification.
Consider the following scenario: a vessel ruptures, LEL alarms go off all over the plant, contract workers (who may not have been trained properly in plant safety) panic, jump into their trucks and race through the vapor cloud in an attempt to evacuate the plant... Couldn't happen? I think it could.
So? In that case the ?hazardous location? will probably extend well beyond those shown on electrical area classification documents. API RP 500 states in section 1.2.1 (Scope)
The following items are beyond the scope of this document:
?
b. catastrophes such as well blowouts or process vessel ruptures. Such extreme conditions require emergency measures at the time of occurrence;
c. the suitability of locations for the placement of non-electrical equipment;
There is similar text in NFPA 497
In the NFPA book, "Electrical Installations in Hazardous Location," the authors site as possible ignition sources: power arcs from electrical equipment, static electricity, mechanical sparks, open flames, hot surfaces, and "other sources." They give many examples of each of these. ALL of these sources must be controlled in a hazardous environment.
The API Subcommittee on Electrical Equipment, hasn?t considered "Electrical Installations in Hazardous Location," authoritative for years; primarily because it tries to apply electrical area classification to ?ALL of these sources [that]must be controlled in a hazardous environment.? This does not mean they are to be ignored, rather electrical area classification is not to be the basis for determining ?ALL of these sources?? The SOEE does consider NFPA 497 authoritative. ?
For legislative guidance in enforcing worker safety measures, look to your OSHA regulations. Also, if your plant handles sufficient quantities of hazardous chemicals they may be required to address these dangers through OSHA's Process Safety Management program.
We finally agree on something.
The proper way to address this issue is through: (1) Engineering controls,(2) Administrative controls, and (3) Personal Protective Equipment.
Engineering controls should always be tried first.
Do you have new area classification drawings? Sometimes, when engineers do not have the time or the budget to completely analyze a change in the process, they will error on the side of safety by creating blanket classifications which may not be necessary. Contacting a good engineering firm that has ample experience in your industry would be a good first step in reviewing your area classification drawings to see if they can be reasonably modified. (Note: area classification drawings specify the height as well as the breadth of the area covered. In many cases, the classified area reaches only 18" above grade. This places the ignition-capable components of the car outside the classified area.)
Proper documentation is a requirement of both OSHA PSM and NEC Section 500.3(B). There are no exceptions.
Engineering solutions may also include: elevating the road to get it out of the area; re-routing the road around the plant, installing block walls on either side of the road to isolate it; or moving pumps, valves, or process piping further away from the road.
Administrative controls should be tried next.
In all the refineries, gas plants, and offshore oil platforms where I have worked, ignition sources are allowed as long as a the proper procedures are followed. These usually include: Job Safety Plans, Safe Work Permits, and Hot Work Permits. The goal is to make sure everyone understands what the dangers are and what is to be done in an emergency. Usually one person constantly monitors the air for combustible gas and shuts down all work if any gas is detected.
Personal Protective Equipment should be tried last. I can't think of any PPE that could be used to make this safe.
Many refining facilities require NOMEX as a general plant practice although it is not legislated requirement.
Finally, please note the following:
Article 514 deals with Gasoline Stations. The classified area where cars are permitted extends only 18" above grade. Even though the vehicle electrical system is in an unclassified area there are signs on the pumps (at least in California there are) which warn you to turn off your engine, not to smoke, turn off all electronic equipment (like radios, cell phones, and pagers), not to re-enter your vehicle while fueling (because of static electricity) and to place plastic fuel containers on the ground when re-fueling them (don't leave them in the truck bed --- static electricity again).
Again, so? These are a separate set of safety practices set by NFPA 30A or API recommendations; i.e., the area classification requirement is establishes as ?extracted? text from NFPA 30A. No smoking, turning off engines and placing fuel containers on the ground are too. The other ?requirements? are actually only recommendations from API. unless they are legislated locally. None of them have anything to do with the electrical area classification since most of the activities, except filling containers, is outside the classified location
Most refineries prohibit the use of cell phones and they require pagers to be listed and labeled as non-incendive devices.
Again these are plant practices, usually recommended by API, but they are beyond the scope of electrical area classification
Most off-shore platforms prohibit anyone from bringing cigarette lighters on board.
I read a safety incident report once of a person who had been carrying a 9-volt battery in his pocket with some loose change. The battery shorted out across a penny and ignited some pocket fluff, which, though startling, was easily extinguished.
Are you saying if he had a butane lighter in his pocket it should be Division 2?
