5.15 Meters, Gauges, and Flow
and the outdoor air duct. Airflow measuring grids must
be sized to give accurate readings at minimum flow. It
may be necessary to reduce the duct size at the station to
permit accurate measurement.
Water flow or energy measuring devices are required for
Thermometers and Gauges. Each piece of mechanical
each chilled water refrigeration machine, hot water boiler,
pump, and connections to district energy plants.
test ports to verify critical parameters, such as capacity,
Individual water flow or energy measuring devices shall
pressures, temperatures, and flow rates. Following are the
be provided for chilled water lines serving computer
rooms and chilled water and hot water lines to outleased
spaces. Flow measuring devices shall be capable of
Thermometers and pressure gauges are required on the
communicating with the central BAS. Water flow and air
suction and discharge of all pumps, chillers, boilers, heat
flow measuring devices shall confirm to ASHRAE
exchangers, cooling coils, heating coils, and cooling
Standard 90.1 requirements.
towers. To avoid pressure gauge tolerance errors, a single
pressure gauge may be installed, valved to sense both
Testing Stations. Permanent or temporary testing stations
supply and return conditions. For coils with less than 0.63
shall be provided for start up and testing of building
L/s (10 gpm) flow, provisions for use of portable
systems. Connections shall be designed so temporary
instruments to check temperatures and pressures shall be
testing equipment can be installed and removed without
shutting down the system.
Duct static pressure gauges shall be provided for the
central air-handling unit air supply fan discharge, branch
take-offs of vertical supply risers and at all duct locations
at which static pressure readings are being monitored to
control the operation of a VAV system.
Differential static pressure gauges shall be placed across
filters in air-handling units and to measure building
pressure relative to the outdoors. A temperature gauge is
required at the outdoor air intake to each air-handling unit.
Flow Measuring Devices. Airflow measuring grids are
required for all central air-handling units. Measuring grids
shall be provided at the supply air duct, return air duct,
Meters, Gauges, and Flow Measuring Devices
Revised March 2005 PBS-P100