Denso Tape Application Instructions


For the protection of pipes, fittings and similar structures from corrosion above ground, buried or immersed. To protect the metal structure from the environment the tapes must cover the entire surface.
Surfaces must be clean and dry. Remove all loose rust, scale and flaking coatings by scraping, wire brushing or blast cleaning.
For small diameter pipes and fittings (e.g. service pipes) apply DENSO PASTE by gloved hand in a thin layer over the entire surface including threads, crevices and pitted areas. For larger areas, brush DENSO PRIMING SOLUTION over the entire area.
(a) Pipes, Rods and Cables:
Select as wide a width of tape as practical, e.g. 75mm wide for 75mm diameter pipe. For buried or immersed applications apply tapes with 55 % overlap to give double thickness. For above ground use overlap tapes by 15mm for widths up to 150mm and 25mm for wider tapes. Press the end of the tape firmly onto the pipe and unroll the tape around the pipe spirally, overlapping itself (see diagram). Apply sufficient tension to conform the tape to the surface without gaps. Do not overstretch. Start a new roll by overlapping the ends by one tape width. Press down all folds and smooth the entire area with special attention to overlaps.
(b) Butt Welded Joints:
As (a) but apply one circumferential turn around the pipe with half the tape width covering the existing pipe coating and half on the bare joint area. Continue to apply the tape spirally with 55% overlap across the joint area until it overlaps the existing pipe coating by half its width. Complete the wrapping with one circumferential turn.
(c) Elbows, Tees, Flanges etc.
Carefully bandage the fitting, pressing down folds and avoiding air gaps. Cover the whole fitting with at least two layers continuing onto the pipe coating either side. At large changes of diameter, bolts and internal angles, make the profile more suitable for wrapping by applying DENSYL MASTIC as a fillet at angles and around bolts. Wrap the profiled joint as above ensuring the tape does not bridge gaps.
(d) Coating Repairs:
Cut away and remove loose coating from the damaged area and smooth or chamfer edges. Prime the exposed metal. For thick coatings, build up the depression with patches of tape or DENSYL MASTIC. Wrap the section of pipe as (a) continuing at least 50mm either side of the damaged area.
For further protection, a separate overwrap of DENSO PVC SELF ADHESIVE TAPE, DENSOTHERM TAPE or DENSOPOL 80 TAPE may be applied spirally over the petrolatum tape. Consult our Technical Sales Department for advice on selection and application of overwraps.
Ensure that the entire surface is covered with no gaps or air pockets. DENSO and DENSYL TAPES cannot be holiday tested due to soft surface. DENSOPOL 4, DENSOPOL PN and DENSO WB TAPES can be holiday tested at SkV for single thickness and 1OkV for double thickness. For further advice on the use of these products consult the manufacturers.