HVAC specification supplement, unknown date

NYC 9/11 Public Portal Document

MAYOR’S OFFICE OF EMERGENCY MANAGEMENT

SUPPLEMENT TO THE HVAC SPECIFICATION

SECTION 15120

1. Paragraph 1.1 .A. 5 - Delete “and the discharge plenum at the emergency generators.”

Add the following;

Discharge plenum at the emergency generators shall be double wall construction 4" thick, built of 16 GA galvanizes sheet metal with high temperature block insulation.

Plenum shall be built as per SMACNA standards for 2" w.g. pressure classification. AU joints, seams, connections and abutments to the building structure shall be sealed with suitable pressure and temperature compounds and gaskets.

Pipe penetrations shall be sealed to prevent air leakage and condensation movement through the seal. Inner sheet shall be of G90 coated galvanized steel with welded connections. All weld on casing interior shall be painted.

Plenum shall be constructed to withstand 133% of the rated pressure without structure failure. Wall and roof deflections at the rated pressure shall not exceed 1/8" per foot.

High temperature block insulation shall be 11 lbs. Per cu. ft. Density molded hydrous calcium silicate with a maximum K factor of 0.42 at 200 degrees F mean temperature.

Insulation shall be securely wired in place with copper clad wire or galvanized steel bands ('A" x .015) on 12" centers.

All joints and voids of insulation shall be filled and pointed with mineral wool cement.

SECTION 15150

1. Add paragraph 1.1 .M

Dampers shown on drawings designated as “F/SM” shall comply with the following;

Dampers shall be pneumatically operated combination fire and smoke Ruskin, Imperial, or approved equal. They shall be provided with factory installed U.L. rated full sleeves. Provide air foil or “V” Blade damper blades supported with shafts and stainless steel bearings to allow daily operation. Provide intermediate supports for damper blades more than 36" long. They shall conform to UL Standard 555S as leakage rated dampers in smoke control systems and when closed shall be the equivalent of a 1-1/2 hour fire damper. Leakage shall conform to Class 2 withjnaximum leakage of 1 OCFM/Sq. Ft. at

NYC-WTC_000173223