"R" Value Calculator SafeBridge Specifications for Builders Builders The SafeBridge system is only compatible with Metroll PurlinsSB Insulation is only available from SafeBridge and Metroll Recommended purlin width 1200mmSB Bridging is telescopic and can be adjusted to suit varying purlin widths.For accurate pricing of Purlin System, please contact us Recommended Purlin Width – 1220mm SB Stabilizer Typical Set Out Click here for Installation Guide Work Method Statement