Application Notes

Gas Detection Application Notes

Engineering guidance for hydrogen leak detection, VOC monitoring, odour control and SF6 switchgear — written around the standards, thresholds and cost models buyers actually ask about.

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Energy Storage Safety

Hydrogen Leak Detection in Battery Rooms and BESS

Lead-acid batteries evolve hydrogen while charging, and lithium-ion cells release it as they begin to fail — hydrogen is among the earliest gases a failing cell emits, often before heat or smoke. This guide is written for BESS integrators, EPCs and O&M teams, and answers three questions: what threshold the codes actually require, which range to specify, and where the sensors go.

  • 4% Hydrogen lower flammability limit (LFL, v/v)
  • 25% LFL NFPA 855 ventilation design target
  • ≈1% Resulting engineering threshold
Updated 2026-09-19 · 9 min read Read the note

All notes

Environmental Monitoring

CEMS Sensor Selection: Sizing SO₂, NOx and O₂ Ranges — and Why Sample Conditioning Decides the Outcome

The sensor that works perfectly at the fence line usually pins at full scale within a week of being mounted on the stack. The cause is not accuracy but scale: the same component spans two to three orders of magnitude between the two locations, and an undersized range raises no error — it simply outputs a very stable full-scale number. This article covers how to size the range backwards from the emission limit and the reference oxygen basis, why the sample-conditioning figures are set where they are, and why the oxygen channel deserves a channel of its own.

≥120 °C Heated sample line: minimum set temperature
4 °C Chiller outlet dew point, held within ±2 °C
Updated 2026-09-26 · 10 min read Read the note →
Semiconductor Specialty Gas Safety

Silane, Diborane and Germane: Leak Detection and Selection for Three Semiconductor Hydrides

Three of the most underestimated cylinders in a fab are silane, diborane and germane. Their occupational exposure limits are 5, 0.1 and 0.2 ppm respectively, while their flammable ranges begin at 0.8% – 2.8% vol — so a set point driven by flammability would wait until personnel were thousands of times over the limit. Written for specialty-gas system integrators, facility designers and EHS teams, this note covers four things: why the exposure limit and the flammability limit must drive separate set points, how to size the range, how large the hydrogen cross-sensitivity actually is, and how the three gases' densities change where detectors go.

5 ppm Silane ACGIH TLV-TWA
0.1 ppm Diborane ACGIH TLV-TWA
Updated 2026-09-26 · 11 min read Read the note →
Industrial Safety

Confined Space Gas Monitoring: O₂, LEL, CO and H₂S Limits and Sensor Selection

Fatal confined space incidents follow a pattern: the lethal entry usually comes after someone already tested the space and found it clear. Gas does not sit still — hydrogen sulphide is heavier than air and creeps up from the pit floor, methane is lighter and collects at the tank roof, and oxygen deficiency has neither smell nor warning. This guide breaks confined space monitoring into the four things you have to get right: the pass/fail limits, the test sequence and sampling points, the four sensors to choose, and the calibration records that prove it. Every figure carries its regulatory source, so it can go straight into an entry procedure or a purchase specification.

19.5–23.5% vol Acceptable oxygen range
< 10% LEL Flammable gas limit for entry
Updated 2026-09-23 · 10 min read Read the note →
Customer Cases

Nitrogen Cabinet O₂ Monitoring: A Tuesday Call, a Friday Delivery

This is a case about lead time. The milestone was the following Tuesday; the existing source answered with a range — out of stock, four weeks, no firm date. Here is exactly what we did, and what we did not do.

0–25% vol Oxygen range, electrochemical
~500 pcs Units supplied on this order
Updated 2026-09-21 · 4 min read Read the note →
Customer Cases

Boundary VOC Monitoring: PID or Electrochemical — Do the Total Cost First

The point of this order was not speed. It was getting the spec right. The client leaned toward PID while needing to hold cost down — two forces pulling against each other until someone turned it into a calculation. Here is the advice we gave, and what was eventually supplied.

0–10 ppm Boundary VOC monitoring range
>5 yrs Electrochemical TVOC rated life
Updated 2026-09-21 · 4 min read Read the note →
Industrial Safety

Combustible Gas Detection: Methane / LPG Leak Alarms and Sensor Selection

The single phrase 'combustible gas' hides two very different behaviours on site: natural gas (methane, CH₄, molecular weight 16) is lighter than air and rises to collect at the ceiling, while LPG (propane/butane, MW 44–58) is heavier and flows along the floor, pooling in low spots. Both burn, both are dangerous — but where you mount the detector, how you set the alarm, and which sensor you choose are completely different. This article settles the points safety and equipment managers most need to get right, with every figure sourced so it can go straight into a monitoring plan.

5% vol Methane lower explosive limit (LEL)
2.1% vol Propane (LPG) lower explosive limit
Updated 2026-09-21 · 8 min read Read the note →
HVAC & Refrigeration

Refrigerant Leak Detection: Low-Power NDIR for R32 / R290

For two decades, air conditioners ran on A1 'non-flammable' refrigerants like R410A and R134a, where leak detection was an environmental 'nice-to-have'. The global push to cut GWP has made R32 (A2L, mildly flammable) and R290 (A3, flammable propane) the mainstream — and turned leak detection from a 'bonus' into a safety necessity: a leak in a plant room or indoor unit can build to a combustible concentration in an enclosed space. This article is for AC OEMs, refrigeration engineers and safety leads: it settles refrigerant classes, leak-detection principle selection and the relevant standards, with every figure sourced.

A2L R32 flammability class (mildly flammable)
A3 R290 flammability class (flammable)
Updated 2026-09-21 · 9 min read Read the note →
Selection & Cost

VOC Sensor vs PID: A 5-Year Cost Comparison for Fixed Monitoring

EHS and environmental managers keep asking the same question: can a cheaper electrochemical VOC sensor replace a PID? The answer depends on what you are measuring, not on price. This article first clarifies what each technology actually measures, then works through a 12-point, 5-year cost model — and states plainly the cases where an electrochemical sensor must not be used as a PID substitute.

6–24 mo Typical PID UV lamp life (varies with duty)
USD 80–200 Replacement lamp price each
Updated 2026-09-19 · 10 min read Read the note →
Environmental Monitoring

Odour Monitoring at Wastewater Treatment Plants

Odour complaints are among the largest single categories of environmental grievance in most cities, and wastewater plants are a frequent target. The difficulty is structural: the legal measurement method is laboratory olfactometry, which answers only "what was the concentration at that moment" — while odour nuisance varies sharply with operating conditions, influent quality, temperature, wind and dewatering cycles. This article covers three things: how the regulations measure odour, what continuous monitoring can add, and how to build a sensor array that is actually useful.

1 ouE/m³ Detection threshold (defined by EN 13725)
10¹–10⁷ Typical dynamic olfactometry range (ouE/m³)
Updated 2026-09-19 · 10 min read Read the note →
Power & Utilities

SF₆ Leak Detection for GIS Switchgear: Why Density Monitoring Is Not Enough

SF₆ has a global warming potential roughly 24,000 times that of CO₂, which is why its leakage is regulated as an environmental issue rather than a purely asset-management one. Many maintenance teams assume a density monitor settles the matter — but density monitoring answers "has the gas in the compartment been lost", not "where is it going". This article sets out how the two layers divide the work, how the regulated leak-check interval is calculated, and one widely overlooked compliance lever: installing a leakage detection system doubles that interval.

≈24,000 SF6 global warming potential (CO₂ = 1)
0.1%/yr Exemption threshold: tested leakage rate must beat this
Updated 2026-09-19 · 9 min read Read the note →
Industrial Safety

Carbon Monoxide Monitoring at Work: Limits, Alarm Set-Points and Sensor Selection

Carbon monoxide (CO) is called the silent killer: colourless, odourless and non-irritating — no human sense can detect it. Almost every site with combustion equipment — LPG forklift warehouses, underground car parks, metallurgical gas areas, confined spaces — sits on its risk list. This article answers the three questions safety officers ask most: which exposure limit applies, how to set the two-stage alarm points, and how to choose sensor range and interference rejection. Every figure carries its source, so the article can be dropped straight into a monitoring plan.

200–250× CO's affinity for haemoglobin vs oxygen
50 ppm OSHA 8-hour PEL (legally enforceable)
Updated 2026-09-19 · 9 min read Read the note →
Environmental Monitoring

Indoor Air Quality Monitoring: What CO₂, TVOC and PM Each Tell You — and How to Measure Them

"CO2 above 1,000 ppm means bad air" — half industry consensus, half the most widespread misconception in the field. ASHRAE's official position paper states flatly that Standard 62.1 has never set a 1,000 ppm limit. This article splits IAQ monitoring into three different jobs — CO₂ for ventilation, TVOC for pollution sources, PM for particulates — lays out the full GB/T 18883-2022 limit table, and explains which sensor principle fits each layer, where to mount it, and how to interlock it with ventilation.

0.10% GB/T 18883 indoor CO₂ limit (1-h mean)
0.60 mg/m³ GB/T 18883 TVOC limit (8-h mean)
Updated 2026-09-19 · 9 min read Read the note →

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