MWRDGC RESPONSE
1:
The existing StormTrap detention tank was originally designed and installed to be watertight, however, no performance requirement (ie. a maximum leakage rate) was imposed on the structure during its construction. During installation, the joints were specified to be less than ¾ inch in width and all joints were specified to be sealed.
Per Section 07 9200, the StormTrap detention tank is to be cleaned and sanitized. After the tank has been cleaned, the joints are to be inspected. Through the inspection, the contractor shall identify and then repair joints to near original condition. Damaged joints that need repair may include joints with no visible sealant or missing joint sealant, joints with gaps due to shifting of structures or shrinkage of joint sealant, or damaged joint sealant. Section 07 9200 does not have a maximum leakage rate performance requirement.
Section 07 9200 specifies polyurethane joint sealant complying with both ASTM C 920 and NSF 61 standards for this work.
Date of Answer: 1/23/2018 1:21:30 PM
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