The tank was sized for a storm.
Measure the one that arrives.
Capacitive level sensing and optical precipitation measurement for SUDS and attenuation, recording what the system did during the storm rather than what a model says it should have done.
Designed to a model, judged on an event
Sustainable drainage arrives as a planning condition. An attenuation tank, a basin or a permeable system is designed to a discharge rate, approved on a model, and then built.
What is rarely installed is anything to show whether it works. The system is assumed to perform until a flood, a pollution incident or an adoption dispute asks for evidence, and at that point the only available answer is the model that was approved years earlier.
The measurement needed is not complicated. Level in the storage and rainfall over the catchment, recorded through the event, describe what actually happened. The difficulty is that both instruments sit in chambers and on roofs that nobody visits.
One building. Seventeen measurement points.
A building measures from the roof to the basement, and from the plant room to the pavement outside.
Wind above the parapet, at the facade and at the kerb. Conditions for ventilation and plant. Rainfall and level for drainage. Position on everything that moves. Measurement for the machinery that keeps the building operating.
Rooftop weather station
The roof is where a building finds out what the weather is actually doing, and it is the only place a met station can go without arguing with the architect.
- MaxiMet GMX551 wind, T, H, P, solar and rainfall in one housing
- MetConnect One Modbus and SDI-12 into the BMS
- WindObserver 75 316 stainless, IP66, for an exposed high roof
Rooftop plant and HVAC
Air handling responds to outside conditions, and a plant deck sheltered by its own parapet is not measuring the same air the intakes are drawing.
- MetConnect THP temperature 0.2 degrees C, humidity 1.5 percent RH
- WindMaster 3-axis for ventilation and air-flow control
- MaxiMet GMX500 wind, temperature, humidity and pressure in one unit
Tall building wind loading
Wind loading and perceived sway are the reasons the structural model exists, and the only way to check the model is to measure the building it produced.
- WindObserver 90 0 to 90 m/s, 316 stainless, no moving parts
- WindMaster Pro 3-axis to 32 Hz for buffeting and vortex work
- WindObserver 75 open head, accurate across a wide flow angle
Facade access and cradles
A building maintenance unit stops at a wind speed, and the crew on the cradle would rather that number came from the facade than the airport.
- WindSonic 60 0 to 60 m/s, 0.5 kg, mounts on the rail or parapet
- WindObserver 75 where the facade position is severely exposed
- Blade position sensors non-contact position feedback on the cradle drive
Tower crane and lifting
An urban lift stops on a wind reading taken at the jib, above a street that will be closed if it goes wrong.
- WindSonic 75 0 to 75 m/s, full-range accuracy published
- WindObserver 90 0 to 90 m/s for tall or exposed jibs
- MaxiMet GMX200 wind only, 0.5 kg, for a temporary works mast
Site hoarding and dust
Dust and noise complaints from a city site arrive with a time on them, and without wind data at the hoarding there is nothing to answer with.
- MaxiMet GMX551 wind, T, H, P, solar and rainfall at the boundary
- MetConnect THP two analogue inputs for dust and noise monitors
- WindSonic 60 a compact wind reference on the hoarding
Pedestrian wind comfort
A tower accelerates wind down its face and around its corners, and the people who feel it are at the bus stop rather than on the roof.
- WindMaster Pro 3-axis to 32 Hz for gust and turbulence at street level
- WindSonic 60 0.5 kg, discreet enough for a street mounting
- MaxiMet GMX200 wind only, for a short pedestrian-comfort survey
Urban heat and outdoor workers
A street of hard surfaces runs hotter than the met office figure, and the people working in it feel radiant heat rather than air temperature.
- MaxiMet GMX552 WBGT heat stress with wind, T, H and P, 1.29 kg, IP66
- MaxiMet GMX300 temperature, humidity and pressure at street level
- MetConnect THP Pt100 input for surface temperature probes
Green roofs and roof irrigation
A green roof is a maintenance liability if it is watered on a timer and a benefit if it is watered on a measurement.
- TruMet PW100 optical rainfall, no bucket to block with substrate
- MaxiMet GMX551 rainfall alongside solar, wind, T, H and P
- MaxiMet GMX301 solar radiation, 0 to 1600 W per square metre
District energy centre
Heat networks and combined heat and power are sized against outside temperature, and they run at their worst efficiency on the day nobody is watching.
- MetConnect THP reference temperature, humidity and pressure
- GS12 Ignition Module up to 12 cylinders, IP67, for CHP engines
- AF120 closed-loop air and fuel ratio control
Smoke control and pressurisation
Stairwell pressurisation and smoke control are commissioned once and then relied on for decades, in the one event where nobody gets to check first.
- MetConnect THP pressure 300 to 1100 hPa, accuracy 0.5 hPa
- Blade position sensors non-contact damper and actuator position feedback
- WindMaster 3-axis air-flow measurement for ventilation control
Barriers, gates and doors
A car park barrier cycles hundreds of times a day, and the sensor proving its position is the part that fails first.
- Blade position sensors non-contact inductive, unlimited-life feedback
- Blade360 contactless rotary position for barrier arms
- Blade Dual Output a second independent channel where redundancy is required
Kerbside air quality
An air quality reading without wind beside it cannot be attributed to the road, the site or the plant, which is exactly what everyone wants to know.
- WindMaster Pro 3-axis to 32 Hz for dispersion at street level
- MetConnect One analogue inputs for third-party analysers
- MaxiMet GMX500 wind, T, H and P alongside the analyser
Drainage, SUDS and attenuation
Sustainable drainage only demonstrates anything if somebody records what the attenuation tank actually did during the storm.
- LevelPro capacitive level, no moving parts to foul
- LevelSlick FEP coated for silty and contaminated water
- TruMet PW100 rainfall intensity to 0 to 200 mm/hr alongside level
Plant room machinery condition
Chillers, pumps and generators fail in a basement nobody visits, and the wear is in the oil before it is in the noise.
- WearDetect oil debris sensing for ferrous wear particles
- LevelPro lubrication and coolant level with no moving parts
- DD1615 level display local indication in the plant room
Ventilation and occupant comfort
Natural ventilation and mixed-mode control open windows on a wind and temperature reading, and get complaints when the reading is from the wrong side of the building.
- WindMaster 3-axis for building and clean-room ventilation control
- MetConnect THP temperature, humidity and pressure into the BMS
- MaxiMet GMX500 one unit, one cable, one output string
Calibration and commissioning evidence
Soft landings, performance in use and a dispute about comfort all come back to whether the instruments were right.
- UKAS-accredited air velocity calibration traceable certification for anemometers
- Multi-parameter calibration six parameters, equipment from any manufacturer
- Recalibration scheduling intervals, reminders and turnaround
Level and rainfall, recorded through the event
Level in the storage is the direct evidence. It shows how full the system got, how quickly it filled and how long it took to empty, which together describe whether the design assumptions held.
Rainfall is the input. Without it, a level record shows what happened but not what caused it, and the performance question is always relative to the event that produced it.
Both have to work in the conditions that create the event. A float in a chamber carrying silt and gross solids is a mechanism in the worst place available, and a tipping bucket cannot resolve the intensity that filled the tank.
Neither will be visited. A chamber is a confined space entry and a roof gauge is a ladder, so the specification decision that matters is how long the installation runs without attention.
No float in a drainage chamber
Drainage water carries silt, grit and gross solids, which is precisely what fouls a float. The measurement then fails during the event it was installed to record.
Gill capacitive level sensors have no float and fully sealed solid-state electronics. LevelPro is corrosion-resistant stainless at IP66 and IP68, and LevelSlick adds a FEP coating for particulate, viscous and corrosive liquids.
Continuous, with nothing to foul
Explore level sensorsThe intensity that filled the tank
Attenuation performance is judged against a design storm, which is defined by intensity and duration. A gauge reporting hourly accumulation has described the volume and lost the shape that matters.
TruMet PW100 uses infrared optical measurement rather than a tipping mechanism, measuring 0 to 200 mm/hr with 5 percent accuracy and 0.1 mm resolution, with one pulse per 0.1 mm output so it replaces a tipping bucket in an existing installation.
Intensity measured, not clipped
View TruMet PW100Adoption, claims and conditions all ask the same thing
Adoption by a drainage authority, an insurance claim after a flood, or discharge of a planning condition all ask whether the system performs as designed, and all of them prefer measurement to modelling.
A monitored system also protects the designer and the developer. Where a downstream problem occurs, being able to show what the attenuation actually did is the difference between a contribution and an assumption.
Labcal is an independent UKAS-accredited laboratory operating to ISO/IEC 17025:2017, calibrating equipment from any manufacturer, which matters where a measurement supports a regulatory or contractual position.
What a drainage system measures
Level in the storage, rainfall over the catchment, and the conditions record that puts both in context.
Level and rainfall
Level sensing
Capacitive liquid level sensors
Continuous level with no float, in stainless or FEP coated construction for water carrying silt and solids.
TruMet PW100
Infrared optical rain gauge
Optical measurement to 0 to 200 mm/hr, resolving the intensity that attenuation performance is judged against.
MaxiMet
All-in-one weather station, no moving parts
Wind, temperature, humidity, pressure, solar radiation and rainfall from one unit where the site keeps a fuller record.
Wider site
MetConnect
Separable sensors for WMO-compliant siting
Separable sensors with analogue and Pt100 inputs where a scheme monitors several points and instruments.
WindSonic
Lightweight 2-axis ultrasonic anemometer
Lightweight ultrasonic wind measurement where the scheme includes ponds, basins or green roofs.
WearDetect
Oil debris sensor
Ferrous debris monitoring on pumps in pumped drainage, where a failure becomes a flood.
Where drainage measurement does the work
Performance evidence
Level through the storm showing how full the system got and how quickly it emptied.
Open storage
Continuous level in features that are also landscape and amenity.
Infiltration
Measuring whether infiltration rates held up after a few years of use.
Handover to authority
Evidence that a system performs as designed before it is adopted.
Availability
Level and pump condition on systems whose failure is a flood rather than a fault.
Conditions
Monitoring required to discharge a drainage condition attached to consent.
UKAS-accredited calibration for six measurement parameters
Labcal is an independent UKAS-accredited calibration laboratory, Lab 0625, operating to ISO/IEC 17025:2017. It provides calibration across gas and air flow, air velocity, liquid flow, pressure, temperature and humidity.
For a drainage scheme carrying level sensors, rain gauges, pressure instruments, thermal probes and data loggers, one accredited laboratory keeps the installation on a single traceable schedule.
Gas meters · Mass flow controllers · Dispensing systems
Anemometers · Pitot tubes · Thermal probes
Flow meters and sensors · Process control equipment
Gauges · Transducers · Manometers · Transmitters
Thermometers · Probes · Thermocouples · Data loggers
Hygrometers · Probes · Transmitters
Reporting from a chamber and a roof
Drainage monitoring points are chambers and roofs, with no mains power in most cases and no routine visit in any of them.
Gill supports environmental monitoring, industrial sensing, embedded electronics and systems integration, so designers, contractors and drainage authorities can bring measurement into loggers, telemetry and asset systems.
Whether the requirement is SDI-12 into a low-power logger, a pulse output replacing a tipping bucket, Modbus into an asset system, or analogue into an existing channel, Gill engineers can support integration from specification through commissioning.
Outputs and options
- SDI-12 : Low-power loggers in chambers
- Pulse output : One pulse per 0.1 mm, replacing a tipping bucket
- Modbus RTU : Asset and telemetry systems
- 4-20 mA & 0-10 V : Existing analogue channels
What the specification looks like in practice
No float in drainage water
Capacitive sensing has no mechanism in water carrying silt, grit and gross solids.
The storm measured properly
Optical rainfall to 0 to 200 mm/hr resolves the intensity that attenuation performance is judged against.
Evidence rather than modelling
A level and rainfall record shows what the system did, which is what adoption and claims actually ask for.
Built for a chamber
Sealed solid-state construction at IP66 and IP68, with a FEP-coated option for the worst water.
Runs without visits
Low-power operation for installations where the next visit is a confined space entry.
Traceable for a regulatory position
Independent UKAS-accredited calibration across six parameters, for equipment from any manufacturer.
Questions about drainage, SUDS and attenuation
That the system performed as designed against a real event rather than a modelled one. Level through the storm shows how full the storage got, how quickly and how long it took to empty.
Rainfall provides the input, without which a level record shows what happened but not what caused it.
Because there is no float to foul in water carrying silt, grit and gross solids. LevelPro is stainless at IP66 and IP68 and LevelSlick adds a FEP coating for the worst of it.
Because it caps the intensity it can resolve and blocks with debris, and attenuation performance is judged against intensity. TruMet PW100 measures 0 to 200 mm/hr with 5 percent accuracy and 0.1 mm resolution.
Usually. The pulse output is one pulse per 0.1 mm, replicating a tipping bucket, so an existing logger configuration generally continues to work.
SDI-12 output suits low-power loggers, which is the usual arrangement. The power budget should be confirmed against the monitoring period as part of specification.
Yes. Labcal is an independent UKAS-accredited calibration laboratory, Lab 0625, operating to ISO/IEC 17025:2017, calibrating equipment from any manufacturer across gas and air flow, air velocity, liquid flow, pressure, temperature and humidity.
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