Doc – Port
GENERAL – Rolling steel doors shall be similar and equal to the DOC-PORT DOOR as manufactured by City-Gates, of Queens, N.Y. Doors shall be designed to withstand a wind-load of 40 pounds per square foot for doors up to 40 ft. wide and 30 pounds for doors over 40 ft. wide, with the principal stress not to exceed 27,000 Ibs. per sq. in. A design analysis of the slats and guides is to be provided with complete shop drawings for approval. Doors shall be installed by manufacturer or his authorized representative, and shall be guaranteed for one year against any defects in material or workmanship.
OPERATION – Chain operated doors shall be provided with reduction gears, sprocket, and galvanized hand chain. Reduction gearing is to be such that the maximum pull on the hand chain does not exceed 35 pounds. Doors indicated on the drawings to be motor operated shall be provided with a motor unit of sufficient capacity to operate the door at an average speed of .67 ft. per second. Motor operator shall be complete with worm gear reduction unit, emergency hand chain, high starting torque motor, geared limit switch which is not affected by use of emergency chain operation. Operator design shall permit motor removal without affecting hand chain operation. Each operator is to be furnished with a reversing magnetic contact and push button station marked “open”, “close”, and “stop”.
CURTAIN – Curtains shall be formed of galvanized steel Interlocking Doc-Port slats rolled in easy curves without sharp bends. Slats shall be #14 U.S. Gauge with a minimum width of 5″ and a minimum crown height of 1-1/4″. Alternate slats are to be equipped with end locks. Both end locks, of galvanized carriage bolts. The bottom of each curtain is to be reinforced with two galvanized steel angles of equal size, not less than 2-1/2″ x 2″ x 3/16″. A replaceable looped neoprene astragal shall provide a continuous contact with the sill. The top of the curtain shall be securely attached to the counterbalance shaft assembly by means of machine bolts.
SPRING COUNTERBALANCE – The curtain shall be counterbalanced at every point in its travel by means of helical torsion springs fixed at each end to tapered cast iron anchors designed to eliminate concentrated strain. Spring are to be high grade steel, oil tempered and heat treated, with the capacity to counterbalance the entire weight of the curtain assembly plus a safety factor of 25 percent. The spring anchors shall transfer the full spring load to a single torsion shaft so that all of the springs shall be adjusted simultaneously and equally by means of the charging wheel. The spring counterbalance is to be housed in a steel pipe, permanently lubricated, and sealed with steel plugs at each end. The pipe is to be such that the deflection of the assembly under curtain load shall not exceed .03″ per foot of span.
BRACKETS – Supporting brackets shall be 3/8″ minimum steel plate with flanges for support of the hood. Bearings are to be of the permanently lubricated ball bearing type to insure free travel of the inner door shaft. GUIDES -Door guides are to be constructed of structural steel angles of 1/4″ minimum thickness assembled to form a groove of 4″ minimum depth. Guides are to have auxiliary locking channels to engage the curtain wind locks under pressure. Guides shall be securely bolted to the opening jambs with 1/2 inch bolts spaced not more than 2′ 6″ on centers.
HOODS – Enclosing hoods of not less than #24 U.S. Gauge galvanized steel shall run continuously between brackets, with intermediate supports as required.
LOCKING DEVICE – Chain operated doors shall be provided with chain locks on the guides, with provision for padlocking. Motor operated doors shall be self-locking through brakes and worm gear reducers.
GALVANIZING AND SHOP PAINTING – Curtain slats and hoods shall receive a 1.75 ounce class pure hot zinc coating per square foot of flat metal conforming to ASTM Designation A93-63T. They shall then be phosphate coated by immersion in a solution containing an oxidizing agent, rinsed in clear water, followed by a rinse in dilute chromic acid and dried. Bottom bars shall be hot dip galvanized 2.0 oz. per sq. ft. All parts of the doors, except bearing surfaces and working parts of mechanism, shall be given one coat of approved zinc dust primer.