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tion 3, Figure 2.3.1 for proper dis- <br />tances. <br />3. Compact backfill carefully over <br />and around the piping system. (See <br />Figure 1.6.1). When using tamp- <br />ing equipment, take care to pre- <br />vent vibration from driving small <br />stones into the pipe wall. <br />The amount of compaction and <br />the type of soil determines the soil <br />modulus for example, pea gravel <br />has a typical modulus of 1,000 psi <br />with no compaction, while sand <br />requires slight compaction (85% <br />Proctor density) to achieve a modu- <br />lus of 1,000 psi. Refer to ASTM <br />D3839 or AWWA C950 for further <br />details. <br />4. Cover the pipe as soon as possible <br />after successful testing to el iminate <br />the chance of damage to the pipe, <br />floatingof the pipe due toflooding, <br />or shifting of the line due to cave- <br />ins. If damage is suspected, the <br />lines should be retested. <br />5. Frozen earth will eventually thaw, <br />leaving the pipe with insufficient <br />support and voids around the pipe. <br />Take care to remove frozen lumps <br />from all backfill materials before <br />backfilling (See Figure 1.6.2). <br />Remember, in all cases, the pipe must <br />be completely surrounded with se- <br />lect backfill (sand or 1/8 -inch to 3/4 - <br />inch pea gravel). Native backfill <br />materials should never be used. In all <br />cases, there must never be voids (ar- <br />eas which do not contain backfill) <br />under or around the pipe. Six inches <br />(150mm) of the fill must be placed <br />under the pipe as bedding material <br />(See Figure 1.6.3). <br />1.6.3 Adhesive Bonding <br />Several basic adhesive systems are <br />available from Smith Fiberglass Prod- <br />ucts. They differ in operating charac- <br />0 <br />..�v41 �. 7;^�', :: six°r '�';"�xa ».x, w;a .fi'."r.t �.."`C';,3a,�fi+§:A ,.'%�'�•:#,� � i' .�. rq{c�-., <br />a`1 <br />J Table <br />..,• ',� . <br />4" (min.) <br />Table..' <br />100 mm..1. .1 <br />`Or <br />!1 6" (i �.) <br />(. S`+ aa, • 1 1 150 mm <br />�- <br />6" <br />150mm <br />Figure 1.6.3 <br />The pipe must be completely surrounded with select backfill (sand or 1/8" to <br />3/4" pea gravel. <br />teristics and working time (pot life) approximate number of bonds per <br />(See Figure 1.6.4). kit. The working life of each kit is <br />Table 1.6.2 lists the adhesive kits, based on an ambient temperature of <br />their recommended usage, and the %5°F (24°C). <br />