Steve McDonald, SIGMA’s National Product Manager for Pipe Restraint Products, has 38 years of experience in the waterworks industry. He joined SIGMA as a product manager from NAPPCO. Here he answers questions from the field about all things restraint related.
Q1: With SIGMA Flange Universal what forms the seal against the flange? Is it an “O” ring?
Answer: SIGMA Flange Universal is a product designed to connect plain-end pipes (ductile iron, steel, C900 PVC, IPS 2241 PVC, HDPE & C909 PVC) to a flanged fitting or flanged appurtenance. Proper compression and sealing is achieved with an O-ring gasket on the face of our adapter middle ring.
Q2: What is CorrSafe?
Answer: Corrsafe is SIGMA’s terminology for “corrosion safe”, an exterior coating available with our restrained joint products for highly aggressive and corrosive soils. The ductile iron components undergo a 7-step process of cleansing to ensure the finest surface and then we apply a cationic epoxy base coating that permeates into the granular surface of the iron which prevents damage, cracking and chipping that is common with baked-on epoxies. We then top coat our products for additional corrosion protection
Q3: My customer installed your One-Lok wedge restrainer (Model SLDE) for ductile iron pipe on AWWA C900 PVC pipe. Is that okay?
Answer: No and we strongly advise that the gland be removed and be reinstalled using our One-Lok Model SLCE that is designed specifically for PVC pipes. The One-Lok for ductile iron pipe requires a much higher torque on the break-off top actuating bolts that Model SLCE which could create undue stress against the pipe wall. Also, the One-Lok SLDE wedge insert has a frontal lip/tooth that is designed to dive into the ductile iron pipe wall under pressure which could be damaging to a PVC pipe surface.