Steam Trap Monitoring Systems

STEAM TRAP MONITORING SYSTEMS

ISSUE:

Steam traps can fail to operate properly. The results can be energy losses when a trap

fails open, or back-up of condensate in the steam piping when a trap fails closed. The

back-up of condensate is dangerous if water-hammer occurs. Water-hammer has the

potential for rupture of valves, pipes, and fittings. The process of manually identifying

failed traps is very time-consuming and typically requires hand-testing at each trap.

Now, wireless and hard-wired electronic technologies with sensors mounted on the

steam traps can allow facility managers to monitor trap failures more easily.

DISCUSSION:

Standard steam traps have no mechanisms to report when, where, and how they have

failed. However, wireless and hard-wired technologies now permit trap testing using

systems that test for cold plugged and blow-through conditions with conductivity and

acoustic sensors. These monitors can be cost effective because they save energy,

reduce consequential damage to the steam lines, eliminate the need for annual trap

surveys, and cut troubleshooting and diagnostic time in the field.

Monitoring systems can be provided which automatically send individual trap failure

signals to a receiver. In some systems the receiver can communicate to a computer work

station. That information can be utilized to create a work order identifying when, where,

and how a trap has failed in order to assign repair priority. Because the conductivity

sensor is integral to the trap, it must be mounted on a trap with an entry port. However,

the acoustic sensor can be clamped on to virtually any trap's inlet pipe and avoid the

necessity for proprietary equipment.

The desired outcome is for a steam trap to operate effectively for its entire useful life,

and upon failure to alarm and announce the need for replacement. Trap monitoring

systems provide this by allowing the trap to complete its useful life, then be promptly

replaced or repaired upon failure.

RECOMMENDATIONS:

Steam trap monitoring systems should be considered for high pressure steam main

drips, medium pressure traps, and for any usage where the trap is hard to reach.

Facilities should contract with vendors to perform baseline trap audits prior to installation,

and vendors should perform follow-up services. Wireless systems are offered by

Armstrong International, and hardwired systems are offered by Spirax-Sarco.

LINKS TO FM TECHNICAL INFORMATION LIBRARY (TIL):

See "HVAC Design Manual" at http://www.va.gov/facmgt/standard/manuals_hvac.asp

See "Outside Steam Distribution Design Manual" at

http://www.va.gov/facmgt/standard/manuals_steam.asp

FOR ADDITIONAL INFORMATION: Contact Jim Shoemaker at 202-565-5176,

Consulting Support Office (183A).

18 January 2007

FM-181A-DA-129

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