COMPLIANCE INFO_2004-2005 - Laserfiche WebLink

Home Browse Search

4 READ THIS FIRST Before beginning the actual assembly procedures,read and make sure you and all individuals involved in the installation thoroughly understand the following suggestions and precau- tions: Matching taper angles for the spigot and the bell make it pos- Matching taper angles allow the joint to mechanically lock up, sible to mechanically"lock up"a joint by wedging the spigot producing a thin line of adhesive called a glue line. into the bell. This produces a very thin line of adhesive called the bond line,or glue line,which is only a few thousandths of an inch thick. In all cases,the bonding surfaces must be clean before ap- Bonding surfaces must be clean. plying adhesive. Joint strength of the bell and spigot joint is essentially con- Joint strength is controlled by the adhesive thickness-thick is trolled by the adhesive thickness between the two matching bad,thin is better. tapered surfaces. The adhesive is relatively brittle in thick sections and fails easily if the bond line is too thick. The me- chanical lock determines adhesive thickness. Joints that are not"locked up"during installation may pass an initial steady pressure test,but can fail prematurely at a later Mechanical locking of the joint is absolutely essential to date due to reduced bond strength caused by the thick adhe- develop full strength of the joint. sive. Therefore,it is essential that the installation crew be fa- miliar with the joint concept and understand the importance of completely inserting and locking the spigot into the bell. The mechanical locking of the joint is absolutely essential to de- velop the full strength of the joint. Using mechanical force(such as hammering against a wood- en block placed against a fitting or bell end of pipe)helps achieve"lock up." NOTE: This is the same mechanical lock Using mechanical force helps achieve joint lock up. of matching tapers that is commonly used on machine tools. For T.A.B.TM (threaded and bonded)joints,special T.A.B. wrenches or Ridgid strap wrenches are recommended to achieve the mechanical lock-up in the joint. Cool weather conditions require special precautions when bonding pipe and fittings. The adhesive is very viscous (thick)when it is cool or when it is applied to cool pipe. This Follow the appropriate installation procedures for warm or thick adhesive can actually be stiff enough to prevent com- cool weather. plete joint"lock up." There are different installation proce- dures for both warm and cool weather installations. This con- cept is often overlooked when a crew installs piping when there are significant temperature variations throughout the day or week. All bonding surfaces must be factory fresh in appearance. When end caps have been lost,surfaces will weather and re- sult in loss of bond strength. When surfaces are weathered, All bonding surfaces must be factory fresh in appearance. retaper spigots and sand bells to achieve a factory fresh ap- pearance. NOTE: T.A.B.COUPLINGS THAT HAVE BEEN WEATHERED MUST BE REPLACED. RED THREAD IIA Pipe & Fittings — i