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f) When a conduit installation changes from underground to above -ground, make the <br />change a minimum of 6" below finished grade. <br />g) Install an expansion fitting when conduit crosses an expansion joint of a structure. <br />h) Use couplings and expansion joints made of the same material as the conduit. <br />i) Ensure that all joints are made as specified by the manufacturer and are waterproof. <br />j) For installations not specifically shown, install the conduit in accordance with <br />National Electrical Code (NEC) and/or National Electrical Safety Code (NESC) <br />requirements. <br />k) When earth backfill and tamping is required, place backfill material in layers <br />approximately 12" thick, and tamp each layer to a density equal to or greater than <br />the adjacent soil. <br />1) When trenching instead of boring, saw cut and repair all pavement and sidewalks <br />encountered. When backfilling trenches in existing pavement, use a commercially <br />available sand -cement (approximately 10:1 mix ratio). <br />m) Provide a standard clearance between underground control cable and electrical <br />service cable or another parallel underground electrical service cable that meets <br />National Electrical Safety Code requirements. <br />n) Install conduit for electrical and low -voltage systems as shown on the plans or <br />referenced to FDOT Design Standards, Index No. 17721. Consider the locations of <br />conduit as shown on the plans as approximate. Construct conduit runs as straight as <br />possible, and obtain the Engineer's/Owner's approval of all major deviations in <br />conduit locations from those shown on the plans. <br />o) Provide an outer duct and innerduct that is suitable for underground use in an <br />ambient temperature range of -32° to 130° F, without degradation of material <br />properties. <br />p) Provide outer duct and innerduct that is resistant to benzene, calcium chloride, <br />ethyl alcohol, fuel oil, gasoline, lubricating oil, potassium chloride, sodium chloride, <br />sodium nitrate, and transformer oil, and is protected against degradation due to <br />oxidation and general corrosion. <br />q) Provide outer duct and innerduct with an outer diameter to a minimum wall <br />thickness ratio that complies with ASTM — D3035, Standard Dimension Ratio (SDR) <br />13.5. <br />r) Provide outer duct and innerduct that meets or exceeds the following: <br />1. ASTM — D1238: Tensile Strength —3000 PSI minimum Elongation —400% <br />minimum <br />2. ASTM — D1238: Melt Index — 0.4 maximum <br />3. ASTM — D1505: Density — 0.941— 0.9 55 g/cc <br />4. ASTM — D1693: Condition B-20% failure, maximum <br />5. ASTM — D2444: Impact — NEMA Standards Publication TC 7 <br />6. ASTM — D3350: Cell Classification — 334420 or 34420 <br />s) Provide outer duct and innerduct with the coefficient of fiction of 0.09 or less. <br />t) Provide 0.5 inch, pre -lubricated, woven polyester tape with a minimum rated tensile <br />strength of 2,500 lbs. <br />7.4.2 HDPE Outer Duct <br />24 <br />