Hazardous Area Class 1 Div1

[Joe McKenna]

I have a solenoid valve in a Class 1 Div 1 area. The solenoid is rated for the area. Is a sealoff reqired on a solenoid. There are no limits switches. Thanks

 

[nakulak]

unless the device is marked intrinsically safe, or it is part of an assembly that is marked intrinsically safe, my belief is that it is a possible source of ignition and therefore requires a sealoff according to articles 500. (just my opinion - you could always consult with the manufacturer)

 

[petersonra]

I have a solenoid valve in a Class 1 Div 1 area. The solenoid is rated for the area. Is a sealoff reqired on a solenoid. There are no limits switches. Thanks

it needs to be XP and have a seal, unless it is intrinsically safe.

 

[rbalex]

I have a solenoid valve in a Class 1 Div 1 area. The solenoid is rated for the area. Is a sealoff reqired on a solenoid. There are no limits switches. Thanks

It may seem counter intuitive, since an enclosure that is required to be explosionproof in Division 2 is also required to be sealed; but a properly rated solenoid in Division 1 would not need a seal unless the conduit opening were 2? or larger. See 501.15 (A)(1)(1) and (2) and the subsequent text and Exceptions.

A solenoid with a proper ?T-rating? is not considered to be a device ??that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation.?

A proper ?T-rating? would not permit a high temperature. Extracted from 501.15(A)(1):

For the purposes of this section, high temperatures shall be considered to be any temperatures exceeding 80 percent of the autoignition temperature in degrees Celsius of the gas or vapor involved.

 

[weressl]

It may seem counter intuitive, since an enclosure that is required to be explosionproof in Division 2 is also required to be sealed; but a properly rated solenoid in Division 1 would not need a seal unless the conduit opening were 2? or larger. See 501.15 (A)(1)(1) and (2) and the subsequent text and Exceptions.

A solenoid with a proper ?T-rating? is not considered to be a device ??that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation.?

A proper ?T-rating? would not permit a high temperature. Extracted from 501.15(A)(1):

Unfortunately I do not think is that straightforward.

Your stipulation would be true IF the manufacturer specifically spelled out that external seal is not required.

Division 1 testing involves in testing the EXTERNAL temperatures developed for the device, not the internal maximum temperatures. Since Division 1 mode presumes internal failure and there is no internal thermal protection for the coil, it is possible that the coil can overheat.

If the solenoid has no explosionproof enclosure, it would indicate that the internal temperatures HAVE been considered and no explosion containment is needed. You still have to install a seal to maintain the explosion containment not of the solenoid, but of the conduit system.

 

[rbalex]

Unfortunately I do not think is that straightforward.

It is very straightforward. I have cited the appropriate Code Sections [501.15 (A)(1)(1) and (2) and the subsequent text and Exceptions.]

Your stipulation would be true IF the manufacturer specifically spelled out that external seal is not required.

What is your basis for this statement?

Division 1 testing involves in testing the EXTERNAL temperatures developed for the device, not the internal maximum temperatures. Since Division 1 mode presumes internal failure and there is no internal thermal protection for the coil, it is possible that the coil can overheat.

This is simply an assertion on you part. Again, what is the basis for this statement?

If the solenoid has no explosionproof enclosure, it would indicate that the internal temperatures HAVE been considered and no explosion containment is needed. You still have to install a seal to maintain the explosion containment not of the solenoid, but of the conduit system.

Where did you get this idea?

 

[weressl]

It is very straightforward. I have cited the appropriate Code Sections [501.15 (A)(1)(1) and (2) and the subsequent text and Exceptions.]
What is your basis for this statement?

This is simply an assertion on you part. Again, what is the basis for this statement?

Where did you get this idea?

The basis of my statement was explained in the paragraph(s) following the assertion.

My assertion is based on the UL testing process for ther approval. There are different testing proecss for each type of equipment and type of construction. The UL testing for Division 1 and Division 2 luminaires, for example, involves the placing of 30-40 RTD's on the external surface of the luminare for Division 1 test and both externally and internally in the case of Division 2 tests. The luminaires built for Division 1 are expected to withstand an internal explosion, eg. it is expected that a failure will produce a source of ignition inside and in that case it is not material to establish and verify a T-rating for the internals of the unit. In the case of Division 2 luminares no internal explosion is permitted so the hottest point must be found both internally and externally for the T-rating.

Your last question concerned a paragraph with several statements and since you weren't specific as to what part do you question, I can not answer it.

It would be helpful if you engage in a dialog, instead of sniping. Thinking does not hurt. Try it sometimes.

 

[rbalex]

The basis of my statement was explained in the paragraph(s) following the assertion.

My assertion is based on the UL testing process for ther approval. There are different testing proecss for each type of equipment and type of construction. The UL testing for Division 1 and Division 2 luminaires, for example, involves the placing of 30-40 RTD's on the external surface of the luminare for Division 1 test and both externally and internally in the case of Division 2 tests. The luminaires built for Division 1 are expected to withstand an internal explosion, eg. it is expected that a failure will produce a source of ignition inside and in that case it is not material to establish and verify a T-rating for the internals of the unit. In the case of Division 2 luminares no internal explosion is permitted so the hottest point must be found both internally and externally for the T-rating.

Your last question concerned a paragraph with several statements and since you weren't specific as to what part do you question, I can not answer it.

It would be helpful if you engage in a dialog, instead of sniping. Thinking does not hurt. Try it sometimes.

I?m sorry I offended you.

My original analysis was correct and I cited the appropriate text which is readily accessible to anyone.

Technically, the testing methods used in the product standards to determine the suitability of the product are irrelevant. The only requirement of the NEC is that they have, in fact, been found suitable.

That the solenoid may fail internally is also irrelevant unless you are asserting that solenoids are ??apparatus, such as switches, circuit breakers, fuses, relays, or resistors, that may produce arcs, sparks, or high temperatures that are considered to be an ignition source in normal operation.? [rbalex underline added]

 

[justdavemamm]

I have a solenoid valve in a Class 1 Div 1 area. The solenoid is rated for the area. Is a sealoff reqired on a solenoid. There are no limits switches. Thanks

Here's my take from what I have seen installed:

1. If the SV is I.S. so you have an I.S. barrier/isolator feeding it, then No.

2. If the SV is XP rated and does not have it's own built in seal, then Yes.

3. If the SV is XP rated and has a built in seal (as documented by the mfg), then No.

 

[weressl]

Here's my take from what I have seen installed:

1. If the SV is I.S. so you have an I.S. barrier/isolator feeding it, then No.

2. If the SV is XP rated and does not have it's own built in seal, then Yes.

3. If the SV is XP rated and has a built in seal (as documented by the mfg), then No.

2. would also be a NO if the entry is 2" or less, as rbalex explained.

 

[rbalex]

Here's my take from what I have seen installed:

1. If the SV is I.S. so you have an I.S. barrier/isolator feeding it, then No.

2. If the SV is XP rated and does not have it's own built in seal, then Yes.

3. If the SV is XP rated and has a built in seal (as documented by the mfg), then No.

What you have seen should not the basis of your analysis; what the NEC says should be. Read Section 501.15 (A)(1) carefully.
Unless you believe solenoids are arcing, sparking or heat producing (ASH) in normal operation, a factory seal is, in and of itself, irrelevant.