Coplanar and In Line type PT

If the question is about lightning transient protection and an I/S barrier, the answer is that each has a different role.

The I/S barrier is mandated in order to protect the hazardous area from electrical faults in the safe area; from faults that would 'travel' from the safe area to the hazardous area in the direction of the red straight arrow in the graphic and cause an arc or a spark in the hazardous area.

The lightning protection is intended to provide some level of protection, typically MOV transient protection, against near lightning strikes.

An I/S barrier would provide some 'fuse' type protection against a lightning strike in the safe area, but no transient 'MOV" type protection.

An I/S barrier would provide no protection to the transmitter from a lightning strike in the hazardous area.

If the installation is in a hazardous area, then the intrinsic safety barrier is required.

But transient protection is optional asset protection or insurance against losing the transmitter asset to the risk of a near lightning strike.

Dear Iris,

Thank you very much for the information, really apprciate it.

i got one more question

1. What the different from FM approved and ATEX approved. From the information i got, FM approved only for US and the ATEX for worlwide, please advice.

The response to the assertion of "FM approved' is "FM approved for what?" Without an answer, the first assertion is worthless.

Factory Mutual (FM) is a private agency in the United States which does testing and approval to given standards, like ANSI standards or the ATEX directive. Tested products that meet the standard receive an FM approval certificate and cite their products as FM approved

For example:

"Explosionproof for Class I, Division 1, Groups A, B, C & D. Dust-Ignitionproof for Class II, Division 1, Groups E, F & G. Suitable for Class III, Division 1. Conduit seals required
within 18" of enclosure, Group A only." or

"Intrinsically Safe for use in Class I, Division 1, Groups A, B, C & D; Class II, Division 1,
Groups E, F & G; Class III, Division 1, T4 at 40°C, T3A at 93°C maximum ambient, when connected in accordance with Honeywell drawing 51205784"

FM also does ATEX testing.

Manufacturers pay for FM testing, whether the produce passes or not. Changes to the product require re-testing by FM.

So FM approved might be for intrinsic safety or for explosion proof, two very different ratings.

All I know about ATEX is that it is a 'directive'. I assume "ATEX approval" means that an independent testing agency has tested the product and issued a letter of compliance. I don't know how that comes about outside of the US.

Dear Iris

So from you explaination...

If the product is FM explosion proof approval, that means the product also passes the ATEX testing for explosion proof

Because in rosemount ordering information, we can choose the FM explosion proof approval or ATEX explosion proof approval, so im confuse which party is the most recognize.

Please advice me if im wrong.

Are the standards for explosion proof in the USA identical to those for ATEX? I don't know; I cannot give you a definitive answer. The Class/Div/group rating used by FM is different than ATEX's Ex II 1D or EX 2 GD designations, for a start.

There are numerous manufacturers whose pressure transmitters have numerous agency approvals, both FM and ATEX. I suspect that there is no difference in the transmitter design or its components or manufacturing, other than the riveted metal tag that identifies the approvals for that unit.

However, the agency approval designation for which the transmitter is ordered from the factory is the one specified in the model number and whose details are stamped onto the SS metal tag riveted to the transmitter body. That metal tag is the one that determines the approval for that specific transmitter.

It's been my experience that those sites that require a specific approval are looking for that approval on the metal tag, and there's only one approval on the metal tag (a minor corollary to a single approval is ATEX does allow multiple listings for ATEX ratings, but the installer is obliged to check the one used and that check 'marks' that given transmitter for life:

Only your experience can answer "which (approval) is most recognized?" because it is where it is used that really counts. I'm in the US. Our sites have been using FM for decades. The only ATEX I deal with is for a skidded project that is destined for Europe. I'm told ATEX now reigns in Europe. Some countries (Canada, Brazil, South Africa, Russia) and even applications, like marine applications, have their own approvals.

If it's a gauge or absolute pressure transmitter then the term "in-line" is typically used for the single process connection at the end of the 'stem'.

In-line transmitters use block and bleed valves or block/bleed and vent manifolds.

Rosemount's 305R 2 valve coplanar might mate to an in-line, I'm not sure. A Rosemount specialist would be better able to answer that.

If it's a DP transmitter, then the choice is
- conventional 3/5 valve manifold

- direct piping (presumably with discrete blocking valves, an equalizing valve, and vents or vent

valves if needed);
- or for some brands, a coplanar valved manifold.

For decades now the unofficial (I've never been able to track down a standard) DP standard for the center-to-center process connection dimension has been 2 1/8" (2.125" or 54mm). 54mm dimension highlighted below:

To my knowledge, all brands universally use and therefore interchange with one another for that dimension. Even Rosemount's 305R 3 valve coplanar manifold uses teh 2.125" center-to-center dimension for the process connections.

I find some plants use the coplanar, others stay with the conventional flange mount manifolds or even fewer plants with direct piping and discrete valves. Many plants use simple instrument valves (Block valve only) to isolate the transmitter, since calibration checks on gauge pressure transmitters is typically quite seldom.

I have little experience with the coplanar design, so I'd be interested in others' experiences with coplanar manifolds.

Dear Iris,

Just registered with CR4....yeahh

Thank you very much for you explaination.

I will contact the rosemount saleperson about the FM and ATEX approval, which one is recognize in asian region. will post the answer here.

For the Coplanar and In line type, im concern how to do selection for it base on process? please advice

FYI

Not the DP type PT.