Electrical Classification Question 1

[SparkOmatix]

I am very much new to the oil and gas industry and gas compression as a whole. I have recently been asked whether or not our compressor stations are up to code with regard to electrical classification. People are referencing API RP500 which is clearly a “Recommended Practice.” My question is this…

Does having a large gas-driven gas compressor, with its sparkplug sparking like a wild woman, automatically make it and its surroundings a Class I Div II area? Note, it’s a good distance from the inlet manifold and separator. Please reference specific CODE/VERBIAGE that supports your claim. All I’m finding is “Recommended Practice” which is different than saying “Thou Shall”.

Your help is GREATLY appreciated!

 

[zdas04]

SparkOmatix,
You are fairly new here so instead of just closing this thread with a very sour taste in my mouth, I'll give you some unsolicited advice.

I am something of an expert on this subject having fought in these trenches for over 20 years. I was going to help until I got to

Please reference specific CODE/VERBIAGE that supports your claim

The people who monitor this forum have a significant portion of the compression expertise in the industry and as long as you provide questions that they find interesting, you can get some amazing information for free. Acting like we owe you something will get you nothing worth having. Many of us here have very firm rules--for free consulting you get opinions.

If you want reference quotations you have to pay for them. I will not provide specific citations in eng-tips.com for free. Ever. In a free forum, if you had stopped before your last two sentences you might have gotten some interesting discussion that might have led you to the rightest answer possible. As far as I'm concerned anyone who provides you with anything in this thread is wasting their time.

David

 

[SparkOmatix]

Thanks David. Perhaps I should bone up on my Forum Etiquette, eh?

 

[SparkOmatix]

If there are those who can overlook my apparent tactless approach at garnering some insight, please feel free to respond to my initial post regarding Electrical Classification as it pertains to Gas Compressors. Thanks in advance!

 

[dcasto]

as it turns out, its the operators choice. As operator you can select the risk level.

BUT, if I were you, I'd go to the vendors of ignition systems and gather up all the facts, digest them and if needed, call in a consultant to help with the decission and the writting of your opinions.

 

[pmover]

SparkOmatix . . .

i concur with zdas04 thoughts, but on this rare occasion, i will respond . . .

authority having jurisdiction is the starting place - DOT will list the requirements and reference documents since the facility is a compressor station (assuming facility is located in USA).

the attached document may also provide you with some further insight.

learn to apply the definitions for hazardous area classifications.

good luck!
-pmover

 

[SparkOmatix]

Thank you PMOVER. The document is indeed helpful. It seems that industry practice for the midstream sector is not to classify the area directly around the compressor as a nonhazardous area. Has anyone else seen this to be true?

 

[zdas04]

In previous versions of API RP 500 there was an exclusion for non-electrical ignition sources. The thinking was that if you have an open flame in a space (or an exhaust manifold that is at a higher temperature than the gas autoignition temperature), then adding intrinsically safe electrical stuff is a waste of time and money. These spaces were "unclassified". The current version has removed the exclusion and added language that you cannot classify a space as "non-hazardous" (which replaced the "unclassified" category) just because it has non-electrical ignition sources. This change was simply a stupid knee-jerk reaction by the nanny society.

Sites that call the area around a compressor "non-hazardous" are relying on the outdated version of API RP 500. Not a bad idea, but not very defensible in court.

There is an explicit exclusion for engine-driven gensets in API RP 500. It is my understanding (not documented anywhere), that this exclusion was intended to cover all engine-driven equipment (including compressors), but that in the horse-trading that accompanies any API document the exclusion (which in earlier versions was an example) became specific.

It may just be an RP, but engineers are expected to use "best available practices". If you sign off on a space being non-hazardous and later someone dies in a fire there, then ignoring the RP has the potential of reaching the standard of "gross negligence" that allows criminal proceedings against engineers and management.

David

 

[dcasto]

Here is a position paper we wrote min the US. DOT doesn't have any prescriptive rules and it is up to individual companies to have a policy in place.


SHIELDED IGNITION

SCOPE:
Because our company, has a target of zero negative incidents, engineering proposes to address shielded ignition components as follows:

We have determined that it is an acceptable risk to systematically replace/install ignition components on all compressor units using a Risk Management approach in conjunction with following the applicable reference standards of, NFPA 37 and the Canadian Standard Association (CSA)

http://www.csa-international.org/who_accepts_csa/

, as follows:
1. Risk management of ignition systems in use in remote unmanned facilities;
2. Use of Canadian Standards Association (CSA) (or equal) certified Class 1 Div 2 Group D components that do not void warranties from engine manufacturers;
3. and a phase in approach that replaces worn or defective components that are not certified Class 1 Div 2 Group D with components that are certified.

DISCUSSION:
The ignition systems on industrial gas spark engines are made up of the following parts:
1. The triggering system or control unit;
2. the control signal wires;
3. the coils;
4. the plug wires and/or leads;
5. and the spark plugs.

Most of the units we have in place have CSA registered Class 1 Div 2 group D Triggering Systems, control wires and to a lesser extent the coils. The plug wires, leads, and plugs are not rated, mainly because installation and maintenance procedures are what cause these elements to lose electrical integrity which may result in an uncontrolled ignition source; a flashover Note 1.

New engine designs and controls have allowed the industry to modify the installation and type of coils and leads. This change allows for a more readily available supply of coils and leads that include CSA certified parts. Class 1 Div 2 spark plugs are available, but a question arises on their use and warranty by the engine manufacturer. Lumen will inventory its use of CSA certified components and the availability of replacement parts.






SUMMARY:

The primary operational focus of our comapany is the health and safety of our employees and any other personnel working at our facilities.

The question of shielded ignition originated from the root cause investigation following a compressor fire a smaller Compressor Station. The action item suggested investigation into replacing the existing ignition systems with a shielded system. The shielded system would be one that meets the Class 1 Div 2 requirements. Other action items such as removal of building walls and the addition of gas detection systems at locations with overhead covers has been completed. These actions changed the engine locations from a Class 1 Div 1 to Div 2.

We are providing a safe work place through the following methods:
1. All operations personnel have been issued and are mandated to wear a personal gas detection device. 2. All operations personnel have been given extensive training on the hazards associated with their areas.
3. A Hot Work Permit program has been put in place and is actively being enforced both for Lumen employees and contract personnel.
4. Overhead structures have either been removed or walls have been removed or reduced in area to increase natural ventilation at locations with remaining overhead structures.
5. Permanent gas detection systems have been installed at all locations with overhead structures.

We believe that the risk of personal injury due to a fire caused from an ignition from the electric ignition system of a compressor unit is very small. We further state that a program pertaining to the systematic replacement of applicable components as discussed above would provide adequate safety assurances for personnel and equipment.

Based on all of the above, we recommend that the initially assigned priority of “2” for item number 6 be changed to a priority “3”.

Note 1: Flashover is when the voltage sent to the spark plug does not fire between the center and ground electrodes within the combustion chamber; instead, it shorts between the metal shell and the terminal nut on the plug exterior causing the engine to misfire. This can occur when the air is highly ionized (such as on a stormy day), or when the insulator is dirty. To reduce flashover NGK has ribbed corrugations on the top portions of the insulator.