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Overview
Every gas detector — whether it’s mounted in a confined space entry station, installed in a marine engine room, or deployed across an industrial process facility — is only as reliable as its last successful calibration. A detector that hasn’t been calibrated against a certified reference gas mixture will drift over time, and a drifted detector in a safety-critical environment is, in practical terms, no better than no detector at all. This is the real operational problem that span gas exists to solve: ensuring that the instruments your team trusts to detect oxygen deficiency, combustible gases, or toxic gas concentrations are actually reading correctly at the point of use.
The 12% Oxygen Balance Nitrogen (12% O2 Bal N2) span gas cylinder is a precision calibration gas mixture formulated for use with portable and fixed oxygen detectors across industrial, marine, and confined space entry applications. With an oxygen concentration of 12% balanced in nitrogen — a mixture specifically selected to fall within the oxygen-deficient range used to set the low-alarm response of most oxygen detection instruments — this cylinder provides the certified reference point needed to verify that a detector will respond accurately and reliably when atmospheric oxygen drops below safe working levels.
What sets this product apart from generic calibration gas options is its direct availability across a practical range of cylinder sizes — from compact 34-litre cylinders suited to field kits and individual instrument sets, to larger 103-litre, 110-litre, and 116-litre industrial cylinders for high-volume calibration programmes and fixed-station use. For safety managers and procurement teams sourcing calibration gas for multi-instrument fleets or ongoing maintenance programmes, the ability to match cylinder volume to actual consumption rate directly reduces waste, cost per calibration, and the frequency of re-order cycles.
Key Features
12% Oxygen Concentration — Low-Alarm Calibration Reference
The 12% O2 concentration in this mixture is specifically formulated to fall within the oxygen-deficient alarm range used by most portable and fixed oxygen detectors. Standard oxygen monitors are typically configured with a low-alarm threshold at 19.5% O2 (the minimum safe atmospheric oxygen level per most regulatory standards) and a second alarm at a lower concentration indicating serious deficiency. Calibrating with a 12% O2 mixture confirms that the instrument responds accurately at a concentration well below the first alarm threshold — verifying that the detector will reliably trigger under conditions that represent a genuine oxygen deficiency hazard for workers in the field.
Balance Gas: Nitrogen (N2)
The balance gas in this mixture is high-purity nitrogen — an inert carrier gas that does not interfere with the electrochemical oxygen sensor response and does not introduce cross-sensitivity complications during calibration. Using nitrogen as the balance gas ensures that the detector’s oxygen sensor is responding only to the certified O2 concentration in the mixture, not to background combustible gases, carbon dioxide, or reactive gas contaminants that could produce an artificially elevated or suppressed sensor reading. For accuracy-critical calibration in safety applications, the carrier gas choice matters, and nitrogen is the industry-standard selection for oxygen sensor calibration mixtures.
Multiple Cylinder Sizes — 34L to 116L
This span gas mixture is available in five cylinder sizes: 34L, 58L, 103L, 110L, and 116L — covering the full range of requirements from individual instrument calibration kits to centralised calibration stations and high-volume industrial programmes. A 34-litre cylinder is well-suited to a field gas detection kit where portability and compact storage are priorities. A 103L or 116L cylinder is the practical choice for a shore-based calibration station, a vessel gas detection maintenance programme, or a safety department calibrating a large fleet of portable instruments on a regular schedule. Selecting the right cylinder volume for actual consumption patterns is one of the most direct ways to manage calibration gas costs.
Precision Mixture — Certified Concentration Accuracy
Calibration gas is only as useful as its concentration accuracy. This mixture is prepared to a certified concentration specification, meaning the actual O2 concentration in the cylinder is verified to fall within the stated tolerance of the nominal 12% value. For gas detectors used in safety-critical applications — confined space entry, marine gas detection, offshore operations, or industrial process environments — calibration against a gas mixture with verified concentration accuracy is the correct technical standard. Calibrating with a mixture of unknown or uncertified concentration does not constitute a valid instrument calibration under most safety management system requirements.
Regulator-Compatible Cylinder Valve
The cylinder is supplied with a standard valve compatible with span gas regulators used for portable gas detector calibration — including the demand-flow and constant-flow regulators commonly used with multi-gas portable instrument calibration. For procurement teams sourcing span gas alongside calibration accessories, compatibility with standard regulator fittings reduces setup time and eliminates the need for adaptors or non-standard connection hardware at the calibration station.
Technical Specifications
Product: Span Gas — Calibration Gas Mixture
Category: Span Gas and Regulator
Gas Mixture: 12% Oxygen (O2), Balance Nitrogen (N2)
Oxygen Concentration: 12% v/v
Balance Gas: Nitrogen (N2)
Cylinder Sizes (C10): 34L / 58L / 103L / 110L / 116L
Application: Oxygen gas detector span calibration
Compatible Instruments: Portable and fixed oxygen detectors and multi-gas monitors with electrochemical O2 sensors
Mixture Type: Binary (O2 / N2)
Benefits
Confirms oxygen detector response in the deficiency range that actually matters for worker safety. A calibration gas mixture at 12% O2 tests the detector’s alarm response at a concentration that represents a serious oxygen deficiency hazard — not just a theoretical set point. If the instrument responds correctly to 12% O2 during calibration, you have a verified data point confirming it will alarm at the oxygen level where action is genuinely required. That confidence cannot be obtained by function-testing with ambient air alone.
Supports regulatory and safety management system compliance for confined space entry and gas detection programmes. Most safety management systems, permit-to-work procedures, and regulatory frameworks for confined space entry require that gas detectors be calibrated before each work period or at defined intervals using certified calibration gas. Sourcing certified 12% O2 Bal N2 span gas provides the reference mixture needed to meet this requirement — and supports the documentation trail that safety audits and regulatory inspections require.
Reduces calibration gas cost through appropriate cylinder size selection. Procuring calibration gas in a cylinder size matched to actual consumption rate directly reduces the cost per calibration and minimises the waste from cylinders that expire before they are fully used. The availability of this mixture in five cylinder sizes — from 34L to 116L — means procurement teams can select the volume that genuinely matches their programme rather than defaulting to a single standard size that may be either insufficient or wasteful for their actual instrument count and calibration frequency.
Simplifies multi-instrument calibration programmes. For safety departments calibrating fleets of oxygen monitors and multi-gas instruments on a scheduled basis, a single consistent span gas specification — the same 12% O2 Bal N2 mixture across all cylinders — eliminates the complexity of managing multiple mixture specifications and reduces the risk of using an incorrect gas on an individual instrument. One specification, one ordering process, one documentation reference.
Who It’s For
The HSE Officer or Safety Manager Running a Confined Space Entry Programme
Your team performs regular confined space entries — in tanks, voids, sewers, or vessels — and your permit-to-work system requires verified gas detector calibration before each entry authorisation. You need a reliable, consistently available supply of certified 12% O2 Bal N2 span gas to support your calibration schedule, and you need the flexibility to order in a cylinder size that matches your instrument count and calibration frequency without overordering and wasting gas to expiry. You’re not looking for the cheapest option — you’re looking for a product that supports the defensibility of your calibration records if something goes wrong on site.
The Marine Safety Officer or Ship’s Engineer
You’re responsible for maintaining portable gas detectors on board a vessel — for confined space entry into cargo tanks, void spaces, and bilge areas, and for compliance with maritime safety requirements for gas detection equipment. You need span gas available on board or through your port supplier for scheduled instrument calibration before every confined space entry operation, and you need a cylinder size that fits into your on-board gas detection kit storage without taking up excessive space in a locker already competing with other safety equipment. The 34L or 58L cylinder sizes are a practical fit for vessel-based calibration requirements.
The Industrial Safety Equipment Distributor or Service Technician
You supply or service portable gas detectors for industrial clients — oil and gas, chemical, construction, or utilities — and your clients rely on you to provide the correct calibration gas alongside the instruments you sell or service. Having 12% O2 Bal N2 span gas available in multiple cylinder sizes allows you to match cylinder volume to each client’s actual programme requirements, provide a complete calibration gas and regulator solution alongside the instrument, and support clients in maintaining their calibration records with the correct certified reference gas for their specific oxygen detector models.
Possible Applications
- Confined space entry — industrial facilities — Calibration of portable oxygen monitors before entry into tanks, vessels, silos, utility vaults, manholes, and other permit-required confined spaces in manufacturing, chemical, and utility environments
- Marine vessel operations — On-board calibration of portable oxygen detectors before confined space entry into cargo tanks, void spaces, ballast tanks, and engine room bilge areas on commercial vessels, tankers, and offshore support vessels
- Oil and gas production facilities — Routine calibration of fixed and portable oxygen monitors in process areas, wellhead facilities, and production platforms where oxygen deficiency or inert gas blanketing creates atmospheric oxygen hazards
- Offshore platforms and FPSOs — Calibration gas supply for platform gas detection maintenance programmes, including scheduled calibration of oxygen monitors installed in enclosed or semi-enclosed platform spaces
- Shipbuilding and ship repair yards — Calibration support for gas detectors used during hot work operations, confined space entry, and tank inspection activities at drydock and repair facilities
- Underground construction and tunnelling — Calibration of oxygen monitors used to verify atmospheric safety in tunnel headings, shafts, and underground working environments before worker entry
- Wastewater treatment and utility infrastructure — Regular calibration of portable oxygen detectors carried by workers entering wet wells, pumping station sumps, sewer systems, and other oxygen-depleted confined spaces
- Safety equipment service and rental companies — Calibration gas supply for gas detector service workshops, rental instrument calibration programmes, and client-site calibration support services
Trust and Certifications
Certified Calibration Gas Mixture
This span gas mixture is supplied as a certified calibration gas with a verified concentration specification. Certified calibration gas is prepared and tested to confirm that the actual gas concentration in the cylinder falls within the declared tolerance of the nominal value — the standard required for instrument calibration to be considered valid under most safety management system frameworks, regulatory requirements, and gas detector manufacturer calibration guidance. A certificate of analysis (CoA) or product certificate confirming the certified mixture specification is available with the cylinder supply for inclusion in calibration records.
Compliance with Gas Detector Calibration Requirements
Gas detectors used for confined space entry, marine safety, and industrial atmospheric monitoring are subject to calibration requirements under a range of regulatory frameworks and industry standards — including OSHA confined space regulations, IMO requirements for vessel gas detection maintenance, and gas detector manufacturer service instructions. The use of a certified span gas mixture at the correct O2 concentration is a core requirement for a valid calibration event under these frameworks. Procuring calibration gas through a recognised supplier with documented mixture specifications supports the evidentiary standard required for safety management system audits and regulatory inspections.
Supplied by Alright Engineering Solutions
The 12% Oxygen Balance Nitrogen span gas cylinder is supplied through Alright Engineering Solutions Pte. Ltd., an authorised distributor of portable and fixed gas detection equipment, calibration gas, and related safety products in Singapore. Alright Engineering Solutions provides calibration gas supply, gas detection equipment, and safety product procurement support for marine, industrial, and offshore clients across the Singapore and regional market.
Accessories and Variants
Span Gas Regulator
A compatible span gas regulator is available to use with this cylinder — providing the controlled, low-pressure output flow required for portable gas detector calibration. Regulators are available in demand-flow and fixed-flow configurations to match the calibration inlet requirements of different portable gas detector models. Contact Alright Engineering Solutions to confirm the correct regulator specification for your instrument make and model.
Available Cylinder Sizes
34 Litres (C10) — Compact size for field calibration kits and individual instrument sets
58 Litres (C10) — Mid-range size for vessel on-board kits and small-fleet calibration programmes
103 Litres (C10) — Standard industrial size for shore-based calibration stations and medium-volume programmes
110 Litres (C10) — High-volume option for large instrument fleets and high-frequency calibration schedules
116 Litres (C10) — Maximum volume option for centralised calibration stations and ongoing supply programmes
Related Calibration Gas Products
Multi-gas calibration mixtures — CO, H2S, LEL, and O2 combination span gases for multi-gas portable monitor calibration
Single-gas calibration cylinders — CO, H2S, SO2, NO2, and other toxic gas span gases for single-gas instrument calibration
Zero gas cylinders — High-purity nitrogen or clean air zero gas for gas detector zero-point verification
Get in Touch
If you need to source 12% Oxygen Balance Nitrogen span gas — whether for a single instrument set, a vessel on-board calibration kit, or an ongoing industrial calibration programme — contact Alright Engineering Solutions to confirm cylinder availability, select the right cylinder size for your programme, and request a formal quote.
Our team can also assist with calibration gas regulator selection, related span gas mixtures, and portable gas detection equipment to support your complete gas detection and confined space entry programme.
📍 3791 Jalan Bukit Merah #06-01, E-Centre @ Redhill, Singapore 159471
