steam and condensate manholes - University of Delaware Facilities ...

UNIVERSITY OF DELAWARE-FACILITIES DESIGN STANDARDS
MAINTENANCE & OPERATIONS CSI: SECTION 15522
UNIVERSITY CONTACT:
STEAM AND CONDENSATE MANHOLES
Maintenance Engineer, Maintenance & Operations
(302) 831-4908
DESIGN REQUIREMENTS
1. Manhole interior dimensions shall be large enough to allow free access for movement.
Height shall be greater than eight-feet (8”) deep.
2. Ceilings are to be removable with plugged lifting holes on each corner.
3. Manhole floors shall be finished and sloped toward a sump.
4. Manholes are provided, for personnel access, valve access from grade and dewatering
from floor sump.
5. Manhole covers shall be a minimum of 36 in. composite construction.
Manufacturer: Fibrelite
6. Manhole lids shall be embossed with the word “Steam”.
7. Manhole rings should extend above final grade to prevent entry of ground water.
8. Manhole top access shall be positioned for the following valves or operated from outside
the manhole at ground level with handles.
Steam main isolation valves
Condensate main isolation valves
Purge valves
Drain valves
9. Manholes are provided with two (2) vents to atmosphere, one for cool air inlet and one
for hot air/steam exhaust. Vents are located at opposite sides of the manhole to promote
air circulation throughout the manhole. Vents are not located within three-fee (3’) of the
personnel access opening. Exhaust vents are more distant from pedestrian walkways than
cool air inlet vents. Vents are gooseneck type or flush grate type, depending on campus
location of manhole.
10. Grate type vent pipe size is eight-inch (8”) minimum. Vent pipes enter side of manhole
within twelve-inch (12”) of ceiling. One full size inlet vent pipe extends down to within
eighteen-inches (18”) of the manhole floor, and one full size exhaust vent extends into the
manhole ten-inch (10”) maximum from the manhole ceiling.
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UNIVERSITY OF DELAWARE-FACILITIES DESIGN STANDARDS
MAINTENANCE & OPERATIONS CSI: SECTION 15522
11. If possible all anchorage and thermal expansion shall be accomplished outside the
manhole.
12. Piping: the final layout of the piping inside manholes shall be reviewed by the University
including all locations of collecting legs, trap discharges, all valves.
13. All drainable, dryable and testable piping closure plate vents shall be extended to near the
top of the manhole while drain shall be plugged.
14. Condensate valves are installed using double-block-and-drain method (similar to doubleblock-and-bleed
gas piping method). One full pipe size spool-piece is provided between
two (2) condensate valves. Spool-piece has one-inch (1”) minimum 3000# thread-o-let,
oriented vertically down on bottom of pipe. Tee with collecting leg (on tee run) and drain
valve (on tee take-off) is connected to thread-o-let for draining purposes (All components
are same pipe size).
DO'S AND DON'TS
DO'S: N/A
DON'TS:
DO NOT Use manholes to function in place of external thrust anchor plates.
DO NOT Use manholes as steam and condensate expansion-thrust anchors.
DO NOT Use manholes to determine the size of the concrete thrust blocks.
DO NOT Place chill water in the chamber of a common manhole.
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