UPP® Secondary Contained Pipe

Where regulations or the site owner call for double-wall lines, UPP® offers secondary contained pipe in four size pairs: 63x50, 75x63, 110x90 and 125x110 mm. The first number is the outer containment and the second the inner carrier. The secondary pipe is rated to 5 bar with a typical burst of 20 bar, and to -0.6 bar vacuum. It is striped black with six green stripes, while the coaxial carrier shows four.

There are two ways to build the double wall. Coaxial pipe arrives with the carrier already inside its jacket, in coils (and, at 75x63 mm, a 10 m stick), for long runs with few joints. Alternatively, a separate secondary sleeve, supplied in straight sticks, slides over primary pipe. That is how the 110x90 mm size is built, with 110 mm sleeve over 90 mm primary.

The fittings keep the interstice continuous and testable. Secondary couplers, reducers and Gemini® elbows, inline joints and tees join the outer wall. Fusion entry seals carry the pipe through sump walls, many with a test port, and double-wall termination fittings keep containment right up to grade at offset fill points. Each test port is a 7 mm Schrader valve under a protective cap. Franklin publishes the interstitial volume per metre for each size, for example 0.66 L/m for 63/50 mm and 2.15 L/m for 110/90 mm, which sizes vacuum or pressure leak testing.

Apex supplies and installs UPP® secondary contained pipework in Lebanon and tests the interstitial space at handover.