CAST TREADS, NOSINGS, AND THRESHOLDS FOR PROTECTION AND LONG WEAR
Wooster quality cast treads, nosings and thresholds contain an even distribution of abrasive grit integrally cast into the surface for anti-slip protection and long wear. Width and length to order. Nosings that are set flush generally should be 3" (76.2 mm), 4" (101.6 mm)or 6" (152.4 mm) in width.
ABRASIVE CASTINGS SPECIFICATION:
Provide Alumogrit, Ferrogrit type ____, size _____, safety treads/nosings as manufactured by Wooster Products Inc. for interior and exterior stairs.
Abrasive shall be #20 virgin grain Aluminum Oxide (AL2O3) abrasive, integrally cast into the walking surface to a minimum depth of 1/32 inch (.79 mm).
Safety nosings up to 6" (152.4 mm) deep with cross-hatched surface being installed into wet concrete shall have a feature strip along the back edge.
Concealed type anchors shall be slotted rivet type, integrally cast into the body of the nosing a minimum of 3/8" (9.53 mm). (Not mushroom type.)
Cast metals used shall conform to the following specification:
Alumogrit (Abrasive cast Aluminum):
No. 43 prime and secondary ingot; low copper content; corrosion resistant.
Ferrogrit (abrasive cast iron):
Class 20 iron; high silicon; machinable, hyper-euctectic.
Any holes or countersinks shall be machine- made, cored holes or countersinks are not acceptable. Screwheads shall not protrude above tread surface.
All Metal types shall have shot-blasted finish; Ferrogrit treads and nosings to have one coat shop-black paint.
Cross hatching and fluting shall be 1/16 inch (1.59 mm) deep minimum and shall be clean and well defined; treads and nosings shall be manufactured, packed and shipped so as to arrive at the jobsite in good condition.
Nosings shall terminate not more than 4" (101.6 mm) from ends of steps for poured concrete stairs; for concrete filled pan stairs, nosings shall be full length of steps less 1/8" (3.05 mm) clearance.
NOTE: Safety nosings going into new poured concrete or cement fill shall be installed before "Initial Set" of the concrete or cement occurs.