NFPA 20 Sensing Lines 2

[anthonyyyg]

Does the current NFPA 20 allow for the use of flexible tubing or hoses on the pressure sensing lines or are they required to be rigid?

The 2007 NFPA 20 reads: "5.29.3 The pressure-sensing line shall be brass, copper, or series 300 stainless steel pipe or tube, and the fittings shall be of 1/2in (15mm) nominal size."

Would corrugated stainless steel tubing (CSST), or stainless steel hose comply?

 

[TravisMack]

The wording in the 2010 edition of NFPA 20 is:

4.30.3* The pressure sensing line shall be brass, rigid copper pipe Types K, L, or M, or Series 300 stainless steel pipe or tube, and the fittings shall be of 1?2 in. (15 mm) nominal size.

A.4.30.3 The use of soft copper tubing is not permitted for a
pressure sensing line because it is easily damaged.

Just my thought, but it seems like they need to be rigid piping.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[NJ1]

The NFPA does define it has to be ridgid but in fact as Travismack mentioned all piping defined under 4.30.3 are ridgid:
4.30.3* The pressure sensing line shall be brass, rigid copper pipe Types K, L, or M, or Series 300 stainless steel pipe or tube, and the fittings shall be of 1?2 in. (15 mm) nominal size.

I believe because of the amount of vibration it needs to be ridgid.

 

[anthonyyyg]

Okay, that makes sense.

Thanks for the quick replies!

 

[NJ1]

Also make sure you install individual sensing lines as required.

 

[anthonyyyg]

Of course

Just looking for ways to simplify installation a bit.

Any suggestions?

 

[pipesnpumps]

I've seen the sensing lines tied in downstream of the pump discharge valve, and with non-supervised block valves in the sensing lines themselves...I would avoid doing that for what should be obvious reasons.

Copper (rigid pipe not tubing) should be cinch to solder in from the pump to the nearby controller. A twenty foot stick and a few elbows would do it. What could be simpler? Something like a braided washing machine hose would physically work, but why spent the big $$ on the pump, controller, dedicated electrical service, fire resistance rated enclosure, etc. and then go cheap on this cheap but important piece.