FM/CSA Certificate with IS : Siemens Sitrans #7NG3136

We're getting Sitrans TH-300 (Siemens #7NG3136-5AC11-ZC11+G10) which has FM certification

with explosion protection method XP,DIP,NI,S. However, the end user needs either FM or CSA certificate under NEC-505 (or 500) with Intriscially Safe (not Non-Incendive) protection method.

As I understand “Non-Incendive” technique through ISA12.12.1 & relevant sections of NEC-500 and found that both intrinsically safe (IS) and non-incendive (NI) use the same basic concept to minimize the risk of ignition of flammable gas or vapour. Both rely on energy limitation with some differences. NI circuits are permitted in Division 2 and Zone 2 classified locations only while IS circuit are suitable to use in Division 1 and 2, and Zone 0,1,2 classified location. Similar to IS barriers, NI barriers are also available. The main difference between two types of equipment is that NI circuits are evaluated for ignition capability under normal operating conditions, while an IS circuits are evaluated under fault conditions. Despite of similarities between NI & IS concepts, field wiring methods are different and both NI & IS needs to be separated.

Is anyone aware about FM or CSA certificate with Intrinsic-Safe (IS) protection method? At the moment, I can't find it on the website.

Please note that I'm aware that Sitrans7NG3136 has IECEx/ATEX certificate with Intrinsic-Safe, but it is not acceptable by end user as NEC compliance is a must.

Much appreciated your quick response.

FM IS certificates are not applicable to 7NG3136 (field mounting/ field indicator)as they're meant for 3211 or 3212 which are head-mounting type.

Have you come across any FM/CSA/UL certificate which says 7NG3136 are Intrinsic-Safe (IS).

I'm really stuck here are as client cannot accept NI (Non-Incendive) option at all! And even worse, no IECEx or ATEX. Looks like I've to transmitter with another vendor....which will be a great hassle!!!

I noted your suggestion and will be more careful nexttime.