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Specifications for safety shut-off unit type USSA

Safety shut-off unit type USSA

The Elster safety shut-off unit type USSA is a safety shut-off for the medium-pressure segment. These types of safety shut-offs have been used extensively in HAS installations.

In combination with the safety shut-off type USSA we have two different constructions in our product line therefore we are able to supply both safety devices for HAS sets. The USSA safety shut-off has an internal bypass and a position indicator.

The type USSA belongs to the brand Elster-Jeavons and is fitted as standard on a gas pressure regulator type J125. The shut-offs can be supplied with under pressure (UPSS), overpressure (OPSS) or a combination of both (OUPSS).

Due to the modular design, this safety shut-off can also be combined with a dust filter. The filter/OPSO set is a combination of the following types of safety devices and the small dust filter type DF.

For technical data concerning the dust filter click here.


For the low pressure versions UPSS-LP, OPSS-LP and OUPSS-LP.

For high pressure versions UPSS-HP, OPSS-HP and OUPSS-HP.

Combination with a filter (DF) FOPSO-LP and FOPSO-HP.

Maximum operating pressure

The maximum inlet pressure = 19.6 barg for the 3/4 “BSP-Tr bolted version.

The maximum inlet pressure = 8.6 barg for the 1 “screwed and DN25 PN16 flanged version.

Operating temperature

-20.0 – +60.0 °C.

Spring ranges

USSA-UPSO – LP = 18 to 500 mbarg.

USSA-OPSO – LP = 18 to 500 mbarg.

USSA-UPSO – HP = 0.5 to 4.0 barg.

Connection sizes

Screwed: 3/4 “and 1” BSP-Tr.

Flanged: DN25 PN16.

Applicable gases

Natural gas, LPG, propane, butane, air, nitrogen and other gases. Not suitable for oxygen O2.


Various adapters are available for the USSA, so that this type can be mounted on different gas pressure regulators. Such as 1800-B2 and 1800/2000 Industry (1823, 1833, 1843, 1853, 1883 and 1893), J125 and J125 Industry (S4, S5, S9, S10 and S12) and Elster MR regulators.