Industry
Air and water flow, temperature, pressure and humidity instruments for commissioning and building operation.
Building services instrumentation is dominated by commissioning. A building is designed to deliver certain conditions, and the instruments exist during construction to demonstrate that it actually does - airflow at each terminal, water flow through each circuit, pressure relationships between spaces, and the temperatures the control system is trying to hold. Most of these measurements are made once, carefully, and then revisited only when the building fails to perform.
That gives the sector a distinctive feature: portability matters about as much as accuracy. The engineer commissioning a building moves between floors, plant rooms and rooftops, so the instruments are hand-held, battery powered and expected to survive being carried around a site. The same instruments are then used for troubleshooting and periodic verification, which is what keeps them relevant long after handover.
The second theme is that the quantities are small and frequently differential. Airflow is often a pressure difference across a terminal or a filter, humidity matters within a narrow band both for comfort and for condensation risk, and the water flow in a circuit may be a fraction of what a process plant would regard as a small flow. An instrument chosen on the basis of its range rather than its ability to resolve small differences frequently turns out to be unusable for the job it was bought for.
Airflow and water flow balancing, terminal and diffuser measurement, pressure relationships and control verification. Portability and repeatability matter more than the finest accuracy, because the result is usually a comparison between terminals rather than an absolute figure.
Boilers, chillers, pumps, heat exchangers and distribution circuits. Flow, temperature, pressure and differential pressure across filters and valves, measured for setting up and for diagnosis.
Temperature, humidity, carbon dioxide and pressure in occupied spaces, feeding the control system and the ventilation strategy.
Heating and cooling energy, electricity consumption and run hours, used to verify performance and to allocate cost between areas or tenants.
| Measurement | What is measured in this sector | Instruments commonly specified |
|---|---|---|
| Airflow and pressure | Air velocity and volume at terminals and in ducts, duct static pressure, and pressure relationships between spaces | Hot-wire and vane anemometers, capture hoods for terminal measurement, and differential-pressure instruments for filters, fans and room pressure relationships |
| Temperature and humidity | Supply, return and space temperature, surface temperature for condensation risk, and relative humidity indoors and outdoors | Portable and fixed temperature and humidity instruments, with sensors chosen so that the reading settles quickly enough to be usable on a walk-round |
| Hydronic flow and energy | Water flow in heating and cooling circuits, differential temperature across heat exchangers, and delivered thermal energy | Ultrasonic clamp-on meters where the pipe cannot be opened, electromagnetic meters in new installations, and thermal energy meters combining flow with a matched temperature pair |
| Pressure and differential | Filter and coil differential pressure, pump head and system pressure | Differential transmitters and portable manometers, with the range matched to the small differentials involved rather than to a general pressure range |
| Gas and indoor air | Carbon dioxide as a ventilation indicator, carbon monoxide from combustion, and refrigerant detection in plant rooms | Indoor air quality monitors, portable detectors for combustion checking, and fixed refrigerant detection in plant rooms and at chiller locations |
| Electrical and energy | Power and energy consumption of individual plant items and of the building as a whole | Power meters and energy meters, with the measurement class matched to what the figure is used for - a tenant charge or a maintenance trend |
Commissioning instruments are carried, so weight, battery life and a fast settling time are part of the requirement rather than conveniences.
Frequently asked
The questions that come up in this sector before an order. If yours is not here, send it with the duty and we will answer it alongside the quotation.
Airflow measurement at terminals and in ducts, water flow through the circuits, differential pressure across filters and between spaces, temperature and humidity, and something to verify that the control system is responding. Which of these dominates depends on the system being commissioned, but the common requirement is portability and a response fast enough to work through a large building. Anything left in the van is not part of the commissioning.
Because air is compressible, the flow profile in a duct is rarely uniform, and at a terminal the discharge is turbulent and directional. A single velocity reading multiplied by an assumed area can be well out, and the result depends heavily on where the probe is placed. That is why terminal measurement with a capture hood or a properly traversed duct measurement is used rather than a single spot reading.
Clamp-on measurement avoids draining and cutting the circuit, which matters in an existing building and in a system that cannot be shut down. In-line meters are more accurate and more stable but require the pipe to be opened and a section to be provided. Where the result is a balance between circuits rather than an absolute figure, clamp-on is frequently adequate and far more practical.
By measuring the differential pressure between the spaces concerned, at a range that matches the very small differences involved, and by doing so with the building in its normal operating state. Door position, temporary openings and the state of the ventilation system all affect the reading, so the measurement conditions belong in the record. An instrument with an unsuitable range will read zero on a differential that is actually correct.
It combines a flow measurement with a matched pair of temperature sensors to give the thermal energy delivered through a circuit, which is what allows consumption to be allocated between areas, tenants or systems. The temperature pair has to be matched and calibrated together, because the differential across the circuit is small and an unmatched pair introduces an error into every reading.
Whether the instrument is for commissioning or permanent installation, the quantities to be measured and their ranges, particularly the small differentials, the settling time and portability needed, the duct or pipe where the measurement is made, the record required, and the environment at the measurement point. Stating whether the result is a comparison or an absolute figure also changes the answer considerably.
Published products
DPM-48 · Panel Meters Reference listing
Panel-mounted digital indicator accepting 4-20 mA, voltage or RTD input, with programmable scaling and relay outputs for local alarm duty.
Send the process conditions and the standard you have to meet, and we will confirm the instrument, availability and documentation that can accompany the order.
Request for quotation
Send the technical detail and we will confirm availability, lead time and terms. In-stock items ship within 48 hours; customized specifications typically take 2-10 days. Minimum order quantity is 1 pc.