2.2.4
Ductwork
**************************************************************************
NOTE: In colder climates, tempering of combustion
air may be required. Add an appropriate paragraph
for tempering combustion air, if required. Delete
this paragraph, if a plenum chamber is not needed.
**************************************************************************
Air ducts connecting the forced-draft fan units with the plenum chamber
shall be designed to convey air with a minimum of pressure loss due to
friction. Ductwork shall be galvanized sheet metal conforming to ASTM A
653/A 653M. Ducts shall be straight and smooth on the inside with laps
made in direction of air flow. Ducts shall have cross-break with enough
center height to assure rigidity in the duct section, shall be angle iron
braced, and shall be completely free of vibration. Access and inspection
doors shall be provided as indicated and required, with a minimum of one in
each section between dampers or items of equipment. Ducts shall be
constructed with long radius elbows having a centerline radius 1-1/2 times
the duct width, or where the space does not permit the use of long radius
elbows, short radius or square elbows with factory-fabricated turning vanes
may be used. Duct joints shall be substantially airtight and shall have
adequate strength for the service, with 38 x 38 x 3 mm 1-1/2 x 1-1/2 x 1/8
inch angles used where required for strength or rigidity. Duct wall
thickness shall be 16 gauge (1.5 mm 0.0598 inch) for ducts 1500 mm 60 inches
or less and 12 gauge (2.66 mm 0.1046 inch) for ducts larger than 1500 mm
60 inches in maximum dimension. Additional ductwork shall be in accordance
with Section 15895 AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST
SYSTEM.
2.3
COMBUSTION CONTROL EQUIPMENT
**************************************************************************
NOTE: If steam boilers are not utilized, all
references to steam pressure controllers shall be
deleted. If hot water boilers are not utilized, all
references to water temperature controllers shall be
deleted.
Controls for facilities with operating Energy
Monitoring and Control Systems (EMCS) will be
specified to be compatible with existing EMCS
controls. Delete reference to multiple boilers if a
single boilers is used.
**************************************************************************
Combustion control equipment shall be provided as a system by a single
manufacturer. Field installed automatic combustion control system shall be
installed in accordance with the manufacturer's recommendations and under
the direct supervision of a representative of the control manufacturer.
[The boiler water temperature shall be controlled by a water temperature
controller.] [The boiler pressure shall be controlled by a steam pressure
controller.] The equipment shall operate either electrically or
pneumatically. On multiple boiler installations, each boiler unit shall
have a completely independent system of controls responding to the load and
to a plant master controller. If recording instruments are provided, a 1
year supply of ink and 400 blank charts for each recorder shall be
furnished.
SECTION 15569A
Page 26
Previous Page
