Laserfiche WebLink
• ALTERNATIVE EXPLOSION PROOF SEALS: <br />Concrete Construction: <br />1. Minimum thickness of the concrete will be 2 feet or equal to <br />one-tenth (1/10) the width or height (whichever is greater) of the <br />entry where the seal is to be constructed. <br />2. The seal shall be hitched into the rib and floor a minimum of twelve <br />(12) inches or anchored into the rib with roof bolts. (see Figure on <br />Page 18) <br />3. The minimum compressive strength of the concrete shall be no less <br />that 3,000 psi (non-air entrained) at the end of a 28 day period. <br />4. The concrete will be pumped (or injected) into the form through <br />injection ports which shall be located within one foot of the roof <br />and spaced no more that 5 feet laterally. <br />5. The concrete will be poured at continual rate, with no interruptions <br />exceeding 30 minutes. <br />6. The concrete will be reinforced with two (2) vertical mats using #4 <br />grade 40 rebar placed on 18 inch centers both ways, or the equivalent <br />reinforcement area. <br />7. At least one seal in each set of seals shall have surveillance tubes <br />}" copper or }" schedule 40 pipe or equivalent and be installed with <br />a valve. Tube fittings shall withstand at least 75 psi. The tube <br />shall be extended at least 30 feet inby the seal. Also, the lowest <br />seal in each set should contain a drainage pipe with a U-tube water <br />trap to prevent damming of water. <br />Flvash Construction: <br />1. Minimum thickness of the Flyash will be 2 feet or equal to <br />one-fourth (}) the width or height (whichever is greater) of the <br />entry where the seal is to be constructed. <br />2. The seal shall be hitched into the rib and floor a minimum of twelve <br />(12) inches. <br />3. The Flyash shall be thoroughly mixed with 10 percent cement by <br />weight. The Flyash will then be mixed with 100 to 115 gallons of <br />water per ton of material. <br />4. The Flyash will be pumped (or injected) into the form through <br />injection ports which shall be located within one foot of the roof <br />and spaced no more that 5 feet laterally. <br />• 5. The Flyash will be poured at continual rate, with no interruptions <br />exceeding 30 minutes. <br />-19- <br />