Using a 3M STFF Joint Sleeve within Section 12 areas of the LU Network

To allow compliance with the LUL fire regulation standards, all joints for use within Section 12 of the London Underground Network must comply with the LUL 1-085 standard.

To enable compliance for joints required in Section 12 areas, 3M developed a universal joint protection system to manage this. It is known as the Smoke, Toxicity, Fire and Fume joint sleeve or STFF for short.

Installation of the STFF sleeve

The sleeve is slipped onto one of the cables ready to be joined and parked back along the cable. The joint is made off in the normal way and the STFF sleeve is now slid over the joint and held in place by two stainless steel cable ties, one at each end.

3m stff joint shield with steel tie 3m stff joint sleeve with steel tie closed
LUL approved HellermannTyton MBT-type stainless steel cable ties should be used to secure the joint sleeve over the joint. A MK9-SST tensioning tool can also be used to achieve maximum tension on the ties.

There are a number of variants of the STFF shield, including a sleeve design for joints or with a closed end, suitable for cable abandonment applications. A retrofit wrap around version can also be supplied if the joint has already been installed.

Suitable LUL Section 12 and Hazardous Area applications

Designed for use with all single or multi core HV and LV cable joints as well as cable abandonment applications, the STFF joint sleeve is approved on the LUL register (Register Number 1106) for use with 3M Cold Shrink jointing systems.

The joint protection sleeve has applications for jointing on LUL projects as well as other hazardous and petrochemical applications, both on and off-shore.

The 3M joint sleeve can only be purchased with the appropriate joint and is not available as a separate item.

For more information on the 3M STFF sleeves applications, prices and availability, please contact our Sales Team.

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