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Preventing steam leaks
Michael Povey looks at the three main locations of steam leaks and how they can be
IN FACILITIES and plants that have
been designed and constructed
to consume as little energy as
possible, it is rare to find steam
leaking from pipes and valves.
However, even in these facilities, unless
they are regularly inspected and
maintained, steam will eventually leak
as gaskets, fittings and other areas age.
And without proper maintenance, the
number of leaks – usually found in pipe
fittings, valves and steam traps – and
the volume of leaked steam will only
Leaks from valves and steam traps can
be further divided into external leaks,
such as those from gland packing, and
internal leaks, where steam escapes
through the seat and into the outlet.
Preventing leaks from pipe fittings
The main causes of steam leaks from
pipe/valve flanged and screwed
connectors are stress from pipes
expanding or contracting due to the
heat of the steam; threaded
components that have loosened due to
that stress; and/or deterioration of
When pipes contract due to a drop in
the temperature of the steam, the nuts
and bolts of the fitting can loosen,
causing a gap to open between the two
pipes from which steam will escape.
If facilities managers find a steam leak,
they should do more than simply
tighten nuts and bolts on the fitting or
replace the gaskets. They should also
investigate the cause of the leak and
consider changing the number and
location of fixed pipe supports or
adding expansion joints. If
countermeasures like these are not
taken, it is likely that the leak will only re-emerge
in the future.
Increasingly, facilities are choosing to
install stainless-steel piping but, owing
to steam temperature, it is more
susceptible to expansion and
contraction than carbon-steel piping.
Care should therefore be taken to install
the fittings of stainless-steel piping
tighter than for carbon-steel piping.
Preventing leaks from valves
The vast majority of external leaks from
valves come from gland packing.
Owing to the construction of valves,
gland leaks can be stopped temporarily
by tightening the valve.
However, in locations where the valve is
opened and closed regularly, it is likely
to start leaking again within a short
period of time. In these locations, it is
recommended that bellows seal valves
be used. These are highly resistant to
gland leakage because of their bellows,
which closes off the internal and
external gland packing.
Internal leakages occur when steam
escapes – often through the valve seat
– and flows through the outlet while the
valve is in the ‘closed’ position. Internal
leaks cannot be seen from the outside
and are therefore difficult to spot, so
using a maintenance tool such as a
stethoscope or device that measures
ultrasonic vibrations is helpful.
It is common for steam to leak from the
seat of valves with both adjustable and
closable valve openings. One way of
preventing this is to use adjustable and
closable valves where necessary, which
eliminates the need for dual-function
valves. However, another effective
method of preventing internal leaks is
to install a separator to remove the
condensate entrained within steam.
Supplying dry steam will prevent the
valve seat from deteriorating.
Preventing leaks from steam traps
For valves and pipe fittings, leaks occur
when the device stops functioning
correctly, but, for steam traps, the loss
of steam that occurs during normal
operation must also be considered.
Steam losses during normal
The amount of steam that leaks from a
steam trap during normal operation
varies depending on the type of trap.
Depending on steam pressure and
condensate volume, when new, a disc
trap can leak up to 10 times the volume
of steam compared with an energy-efficient
Free Float® trap from TLV Euro
Engineering. For this reason, we
recommend selecting Free Float® traps
to reduce steam loss during normal
Leaks from failed traps
Steam that leaks from even one failed
trap can represent a significant financial
loss, and data from our own global
steam trap assessments shows that,
prior to assessment, an average of
betweem 5% and 10% of all steam traps
in facilities leaked steam.
By identifying leaking traps and
swapping them with energy-efficient
Free Float® traps, facilities can achieve
significant energy savings.
Michael Povey is general manager at
TLV Euro Engineering
For more information:
Tel: 01242 227223
the number of
leaks and the
will only ever