8/21/2019 CHE 0207 Facts_Steam Trap Installation

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Department Editor: Rebekkah Marshall 

Steam Trap

Installation

STEAM TRAP INSTALLATION

“BEST PRACTICES”

A steam trap has two

major functions, 1) toremove condensate asquickly as it is formed and2) to prevent steam dis-charge. There are certaininstallation faults that nega-tively impact the ability fortraps to effectively performthese functions.

A high percentage ofsteam trap failures are simply due toincorrect installation.

Proper installation should providesix years of maintenance-free opera-

tion. The “best practices” for steamtrap installations are outlined below:

1. The most important rule to remem-ber for steam-trap installation is oneof Mother Nature’s Laws — gravity  (Figure 1). Condensate must flowfrom the process to the steam trapby the forces of gravity. Pressureand velocity can not be relied onto remove the condensate from theprocess.

2. Determine the steam leak rate of thenew steam traps that are being pur-chased, per the following leak rate

standards.  a. PTC-39

  b. ISO 7841

  All steam traps leak a quantifiableamount of steam, and the consumershould specify steam traps with theleast amount of steam loss to pre-vent unnecessary energy loss.

3. Steam traps with 1 in. or smallerconnections should use tubing withtube connectors to avoid leak pointssuch as threaded connections.Threaded connections are obvious

sources of leaks in the system dueto expansion, contraction and cor-rosion that occurs in a steam system(Figure 2).

4. There are steam-component manu-facturers that have tube connectionsavailable for steam trap installa-tions. Ensure that the material pres-sure ratings are acceptable.

5. Never reduce diameter of the tub-ing/piping before the steam trap orreduce connection size of the steamtrap. Piping from the process to thesteam trap should always be equal

to or larger than the process outletconnection. For example, a steamunit heater with a 1-in. condensate

outlet would require 1 in. or largertubing/piping from the unit heaterto a same connection size on thesteam trap.

6. Expand the tube/pipe diameterdownstream of the discharge con-

nection of the steam trap. For ex-ample, 1-in. (connection) steam-trapdischarge tubing/piping should beincreased to 1.25 in. or 1.5 in.

7. Steam traps with a connection sizeof 1 in. or smaller should be con-nected to the tubing or piping withuniversal mounts. The universalmount provides the ability to con-nect the steam trap to the applica-tion with two bolts, thus dramaticallyreducing the time for installation ofa steam trap.

9. Include a strainer as part of the

installation of a steam trap. Thestrainer can be accomplished by thefollowing:

  a. External strainer ahead of thesteam trap

  b. Steam trap with integral strainer

  c. Universal mount with an integralstrainer

  The use of a strainer will eliminateor reduce premature failures ofsteam trap due to corrosion.

10. When installing an external orinternal strainer, always install a

blow-off valve on the strainer. Thisallows the strainer to be blowndown during operation and, more

importantly, permits the steam trapcavity to be safely depressurizedduring service.

11. Always install the steam trap in alocation that is accessible by plantpersonnel.

12. Install a visual indication of thesteam trap performance on allprocess applications. The visual in-dication can be a sight glass or testvalve.

13. Locate the steam trap below thelowest condensate discharge pointof the equipment.

14. Never install a rise in the pipeahead of a steam trap.

15. Check valves should be installed

after the steam traps in most appli-cations.

16. Develop and maintain installationstandards for all applications.

17. Follow codes.

  a. Material test reports on all com-ponents (steam traps, connectiondevices, and so on)

  b. B31.1 Piping code

Reference

Steam Trap Installation “Best Practices”,Plant Support & Evaluations, Inc., used withpermission. (For more information, visit

www.plantsupport.com or contact KellyPaffel at kelly.paffel@plantsuppport.com.)

FIGURE 1.  The proper installa-tion of a steam trap on processheat transfer requires a 24-in. mini-mum from the steam supply line tothe steam-trap inlet and an 18-in.maximum from the vertical leg tothe steam trap

FIGURE 2.  Steam-line drip-legsteam-trap installation using tubingand tubing connectors