with slip resistant finish) shall be provided in the concrete top. For
concrete shallow trench systems, a single 150 mm 6 inch gooseneck pipe
shall be used to allow steam to exit the valve manhole if a leak or
excessive heat loss is present; the gooseneck shall be installed off to one
side of the valve manhole concrete top to minimize pedestrian traffic
interference. For direct buried systems, two 150 mm 6 inch goosenecks
shall be used. One shall extend below the top; the other shall be similar
but shall extend to within 600 mm 2 feet of the manhole floor to provide
natural air movement.] Valve manhole sides shall be constructed by one
monolithic pour and shall extend not less than 150 mm 6 inches above grade
unless otherwise stated. Valve manholes shall be waterproofed in
accordance with Section 07131 ELASTOMERIC SHEET WATERPROOFING. All steel
components shall be protected from corrosion.
2.13.2
Ladders
Valve manhole ladders shall be steel, shall have nonslip surfaces, and
shall consist of uprights with steps or rungs. Ladders shall not be less
than 406.4 mm 16 inches in width, with 19.1 mm 3/4 inch diameter rungs,
spaced 304.8 mm 12 inches apart. The two stringers shall be a minimum 9.5
mm 3/8 inch thick and 63.5 mm 2-1/2 inches wide. Ladders shall be
adequately anchored to the wall by means of steel inserts spaced not more
than 2 m 6 feet apart vertically, and installed to provide at least 150 mm
6 inches of space between the wall and rungs. Ladders and inserts shall be
galvanized after fabrication in conformance with ASTM A 123/A 123M.
2.13.3
Pipe Sleeves
Pipe sleeves of sufficient length to pass through valve manhole or building
walls shall be provided. Pipe sleeves shall be zinc-coated steel pipe,
conforming to the requirement of ASTM A 53/A 53M, Schedule 40 or standard
weight. The pipe sleeves shall be secured in the proper position and
location during construction of the valve manhole or building wall. For
manhole top penetrations, the diameter of the pipe sleeve will be large
enough to allow at least 6 mm 1/4 inch of clearance between the pipe
insulation and the sleeve, and, the sleeve will be sized to accommodate the
specific mechanical seal size used for the [conduit] [or] [uninsulated
chilled water pipe] penetration. The space between the sleeve and the pipe
casing, and the caulking and sealing materials shall be selected so there
shall be NO electrical continuity between the pipe sleeve and the pipe
casing when finished.
2.13.3.1
Pipe Sleeves Through Valve Manhole Cover
Insulation shall be continuous through sleeves as shown on the drawings.
Aluminum jacket shall be provided over the insulation. Aluminum jacket
shall be smooth sheet 0.4064 mm 0.016 inch nominal thickness, ASTM B 209M
ASTM B 209. Where penetrating valve manhole top, pipe shall be insulated
as required for valve manhole service up to a point flush with the top of
the flashing and the end of the insulation shall be sealed with waterproof
coating. Insulation exposed to the weather shall butt tightly against the
flashing and valve manhole insulation, and the aluminum jacket required for
piping exposed to the weather shall extend 50 mm 2 inches beyond the
insulation to form a counterflashing. The entire valve manhole top
penetration shall be flashed and counterflashed as shown on the drawings.
Waterproof coating shall conform to ASTM D 2822, Type I.
SECTION 02560
Page 21
Previous Page
