COMPLIANCE INFO_2008-2010 - Laserfiche WebLink

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E E IMPORTANT - READ THIS FIRST Before beginning the actual assembly procedures, read and verily all individuals involved in the installation thoroughly understand the following suggestions and precautions. Matching taper angles for the spigot and the bell make it possible to mechanically "lock up" a joint by wedging the spigot into the bell. This produces a very thin line of ad- hesive called the bond line, or glue line, that is only a few thousandths of an inch thick. Read This First Matching taper angles allows the joint to mechanically lock up, producing a thin line of adhesive called a glue line. In all cases, the bonding surfaces must be clean before ap- Bonding surfaces must be dean. plying adhesive. Joint strength of the bell and spigot joint is controlled by the Joint strength is controlled by the adhesive thickness - thin adhesive thickness between the two matching tapered sur- is good, thick is bad. faces. The adhesive is relatively brittle in thick sections and fails easily if the bond line is too thick. The mechanical 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 date due to reduced bond strength caused by the thick adhesive. Therefore, it is essential that the installation crew be familiar with the joint concept and understand the impor- tance of completely inserting and locking the spigot into the bell. The mechanical locking of the joint is essential to de- velop the full strength of the joint. Using the mechanical force (such as hammering against a wooden block placed against a fitting or bell end of pipe) helps achieve "lock up." NOTE: This is the same me- chanical lock of matching tapers that is commonly used in machine tools. For T.A.B. (threaded and bonded) joints, special TA.B. wrenches or Ridgid strap wrenches are rec- ommended to achieve the mechanical lock up of 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 thick adhesive can actually be stiff enough to prevent com- plete joint "lock up." There are different installation proce- dures for both warm and cool weather installations. This concept is often overlooked when a crew installs piping and there are significant temperature variations throughout the day or week. Mechanical locking of the joint is absolutely essential to develop full strength of the joint. Using mechanical force helps achieve joint lock up. Follow the appropriate installation procedures for warm or cool weather. All bonding surfaces must be factory fresh in appearance. All bonding surfaces must be factory fresh in appearance. When end caps have been lost, surfaces will weatherand re- sult in loss of bond strength. When surfaces are weathered, retaper spigots and sand bells to achieve a factory fresh appearance. NOTE: DO NOT USE T.A.B. COUPLINGS THATARE WEATHERED.