HTM 02-01 vs NFPA 99: Which Medical Gas Standard Applies in India?

The straight answer: neither standard is mandatory in India, and competent Indian hospitals design to a blend of all three. HTM 02-01 supplies the sizing and testing methodology, NFPA 99 supplies the redundancy and installer-qualification philosophy, ISO 7396-1 supplies the safety architecture and the component certification chain, and BIS standards plus PESO licensing supply the Indian statutory layer. A tender that names only one of them is usually a tender that has not been thought about.

That is not a fudge. It is the correct engineering answer to a specific regulatory situation: India has no single mandatory national engineering code for medical gas pipeline systems, and NABH — the body most likely to inspect the result — does not publish one either. NABH assesses whether you designed to a recognised standard and whether you can prove it.

What each document actually is

	HTM 02-01	NFPA 99	ISO 7396-1
Full name	Health Technical Memorandum 02-01: Medical gas pipeline systems	NFPA 99, Health Care Facilities Code	Medical gas pipeline systems — Part 1: Pipeline systems for compressed medical gases and vacuum
Issued by	UK Department of Health / NHS estates function	National Fire Protection Association, USA	International Organization for Standardization (ISO/TC 121)
Legal status in its home country	Guidance, but effectively mandatory in NHS estates	A consensus code adopted by reference into US regulation, including federal healthcare requirements	Voluntary international standard; harmonised in Europe, where MGPS is regulated as a medical device
Legal status in India	None. Referenced by choice	None. Referenced by choice	None. Referenced by choice, but the component chain depends on it
Structure	Part A: design, installation, validation and verification. Part B: operational management	A code covering the whole healthcare facility, with a dedicated gas and vacuum systems chapter	A safety and performance standard organised around risk management
Character	Highly prescriptive and dimensional	Prescriptive on installation and qualification, risk-graded on application	Performance and safety oriented, less prescriptive on numbers
Revision behaviour	Revised and supplemented periodically	Revised on a roughly three-year cycle	Revised periodically, with amendments

Note the third row. NFPA 99 has genuine legal force in the United States because it is adopted by reference; HTM 02-01 has quasi-legal force inside the NHS because it is the estate standard. Neither carries that weight in India. What they carry instead is credibility — with an NABH assessor, with a JCI assessor, and with an insurer after an incident.

The comparison that matters

Dimension	HTM 02-01	NFPA 99	Practical consequence in India
Design flow basis	Assigns a design flow to each terminal unit type, then applies departmental diversity factors to arrive at system flow. Methodology is set out explicitly	Sizes systems against demand, with less prescriptive tabulated diversity guidance	HTM is the more usable document for an engineer sizing copper. Most Indian design calculations are HTM-derived
Pipe material	Copper tube to BS EN 13348, supplied degreased, internally cleaned and capped	Copper tube to ASTM B819 (medical gas tube), Type K or L, cleaned for oxygen service and capped	Functionally equivalent intent, different specifications. Name one and require mill test certificates. Do not write “as per HTM/NFPA” and accept plumbing-grade copper
Jointing	Silver brazing with a continuous inert gas purge; brazer competence required	Brazing to a qualified procedure with nitrogen purge; brazers qualified to a recognised welding/brazing qualification standard	Identical physics. The nitrogen purge is the single most commonly skipped step on Indian sites and produces internal oxide scale that later reaches ventilators
Source of supply philosophy	Duplex/automatic supply arrangements with an emergency reserve and defined emergency supply connection points on the pipeline	Explicit primary / secondary / reserve three-source structure for the highest risk category	The NFPA framing is easier to specify and to audit. Adopt three sources for oxygen regardless of which document you cite
Risk grading	Design consequence handled through system design and operational management	Formal risk categories (1 to 4) determined by the clinical consequence of failure, driving system requirements	Useful in mixed facilities — a day-care clinic and a tertiary ICU should not get identical systems
Alarms	Central/master panel, area alarm panels and plant alarms, with defined alarm conditions and repeat indication at staffed locations	Master alarms at two locations, one continuously staffed; area alarms serving defined spaces; local alarms at source equipment	Converge: master panel duplicated with one at a 24×7 staffed point, area panels per department, all with test facility
Terminal units	Gas-specific probes to the British Standard pattern	Gas-specific DISS threaded connectors and quick-connects to US practice	Choose one system hospital-wide. Mixed estates are the origin of most adaptor improvisation
Testing and commissioning	A staged regime with named roles — Authorised Person, Competent Person, Quality Controller — and a permit-to-work system. Gas quality is signed off by a Quality Controller, in the UK typically a pharmacist, before clinical release	A defined verification process performed by a party independent of the installer, holding a recognised verifier certification	The independence requirement is the more transferable idea. Never let the installing contractor be the only party certifying its own work
Personnel qualification	Role-based competence framework, formally appointed in writing	Certification scheme for installers, inspectors, verifiers and maintenance personnel	Indian tenders should demand named, evidenced competence for brazers and testers, not a company-level claim
Operational management	Part B is a full operational manual — permit to work, maintenance, roles, records	Operational requirements are present but lighter, with maintenance addressed in the code	HTM Part B is the better template for a hospital’s own MGPS operating procedure
Documentation	Extensive prescribed record set through design, installation, validation and handover	Verification report with specified test results	Both satisfy NABH if actually produced. Neither helps if the file is missing

Where the two genuinely diverge

Most of the differences above are dialect. Four are real, and they change build decisions.

1. Who is allowed to say the system is safe. NFPA 99 institutionalises independence: verification is performed by someone who did not install the system and who holds a specific certification for that role. HTM 02-01 institutionalises accountability through named appointed roles, and adds a genuinely distinctive control — quality of gas is signed off by a Quality Controller, in UK practice usually a pharmacist, and the system is not released for clinical use until that signature exists. Indian projects tend to collapse both models into “the contractor tested it.” That is the single most consequential divergence for a hospital to resolve, and the resolution is cheap: appoint an independent third-party tester in the contract, and name a hospital officer who signs for clinical release.

2. Redundancy is explicit in one and implicit in the other. NFPA 99’s primary/secondary/reserve structure is a specification you can put in a tender and check on site. HTM’s arrangement achieves comparable robustness but expresses it through supply system design and emergency connection provisions. For Indian oxygen systems after 2021, the explicit version is better: it forces the conversation about what happens when the PSA plant is down and the tanker is late.

3. Connector systems are mutually incompatible. This is not a quality difference; it is a decision. A British-pattern probe will not engage a DISS outlet, and every adaptor in a hospital is a small, permanent safety liability. Pick one and write it into every subsequent purchase order, including equipment hoses.

4. NFPA 99 is a whole-facility code, HTM 02-01 is a system document. NFPA 99 also covers electrical systems, gas equipment, emergency management and fire aspects of healthcare facilities, and it comes from a fire-safety lineage. If your project is being reviewed against NFPA 99, understand that the medical gas chapter is one part of a much larger set of obligations.

ISO 7396-1: the baseline both sit on

ISO 7396-1 is the international consensus standard for pipeline systems carrying compressed medical gases and vacuum. It is less useful than HTM for sizing a pipe and less useful than NFPA for structuring redundancy, and that is by design — it is written around safety architecture and risk management rather than dimensions.

What it does that neither national document does:

• It anchors the component certification chain. Terminal units are certified to ISO 9170-1, low-pressure flexible hose assemblies to ISO 5359, anaesthetic gas scavenging to ISO 7396-2. When you ask a supplier for evidence that an outlet is genuinely non-interchangeable, this is the certificate you are asking for.
• It requires risk management over the system as a whole, aligned to the general medical device risk management approach, rather than compliance with a list.
• It is jurisdiction-neutral, which is exactly why it works as the common reference in a country that has adopted neither HTM nor NFPA.
• In Europe it is harmonised such that a medical gas pipeline system is treated as a medical device, which is a helpful mental model even where it has no legal effect: an MGPS is a life-support device that happens to be built in place.

The clean way to think about the three: ISO 7396-1 says what the system must be safe against, HTM 02-01 says how big to make it and how to prove it, NFPA 99 says how many sources it needs and who is qualified to touch it.

The Indian regulatory layer

None of the above is Indian law. This is.

BIS / IS standards. The Bureau of Indian Standards maintains standards touching medical gases, cylinders and anaesthetic apparatus. The IS 7396 series on colour identification of gas cylinders and containers is the one most frequently cited in Indian tenders, and colour identification is genuinely enforced in practice. Indian tender boilerplate often lists IS numbers copied from older documents; check the current list and current status of any IS number directly with BIS rather than trusting the boilerplate, because standards get amended, superseded and withdrawn.

PESO. The Petroleum and Explosives Safety Organisation is the statutory authority for compressed and cryogenic gas storage. Bulk liquid medical oxygen vessels fall under the Static and Mobile Pressure Vessels (Unfired) Rules, and cylinder storage and manifold rooms fall under the Gas Cylinders Rules. Both rule sets are amended periodically. Practically, this means an LMO installation requires approved siting, approved vessel and fittings, statutory distances, and a licence — and the licence is a document an NABH assessor may well ask to see. Start the PESO process early; it is a common cause of commissioning delay and it is not something a pipeline contractor can compress.

Drug regulation. Medical oxygen is regulated as a drug in India, with pharmacopoeial monographs for both high-purity oxygen and the roughly 93% oxygen produced by pressure swing adsorption. If your hospital generates oxygen on site, understand the regulatory position of that generation and of the purity testing regime attached to it, and keep the purity certificates.

Fire and building. The National Building Code and state fire regulations govern the manifold room, plant room and cylinder storage from a fire safety standpoint, and local fire NOC conditions are frequently the binding constraint on where the manifold room can go.

NABH. No engineering code of its own. It audits the evidence: design calculations with stated assumptions, as-built drawings with valve and zone identification, material certificates, the full commissioning and validation dossier, gas purity certificates, calibration records for alarm panels and gauges, a documented preventive maintenance schedule with completed logs, a permit-to-work procedure, emergency gas failure procedures, and staff training records. The broader documentation logic is covered in NABH requirements for operation theatres, and it applies identically here — hospitals lose points for missing paperwork far more often than for defective pipework.

What to actually write in an Indian tender

The most common failure in Indian MGPS procurement is a specification that says “system shall be as per HTM 02-01 / NFPA 99 / ISO 7396-1” and nothing else. That clause is unenforceable: it names three documents with different requirements, states no design basis, and gives a bidder no obligation it can be held to. Every bidder prices the cheapest interpretation, and the hospital ends up comparing quotations that are not comparable.

Specify structurally instead. The following is specimen language to adapt, not to paste unread — your consultant must reconcile it against your actual clinical brief and the current editions of the documents named.

Design basis

The Contractor shall design the medical gas pipeline system in accordance with the current edition of HTM 02-01 Part A for design flow rates, diversity factors, pipeline sizing and the testing and commissioning regime. Design calculations shall be submitted for approval and shall state, per department, the terminal unit schedule, the assumed design flow per terminal, the diversity factor applied, the resulting system flow, and the calculated pressure drop from source to the most remote terminal on each service. Diversity factors for intensive care, high dependency, neonatal and emergency areas shall be stated separately from ward areas and shall be justified. The Contractor shall state the surge headroom provided on oxygen above the calculated diversified demand.

Sources and redundancy

Oxygen shall be provided from three independent sources arranged as primary, secondary and reserve in accordance with the philosophy of NFPA 99 for the highest risk category, together with an emergency supply connection point located outside the building and accessible to a delivery vehicle. Medical air, surgical air and vacuum plants shall be duplex or triplex such that any single unit may be isolated for maintenance while the remaining units carry the full diversified design load, with automatic changeover annunciated at the master alarm panel.

Materials and workmanship

Pipeline shall be seamless phosphorus-deoxidised copper tube to BS EN 13348, supplied degreased, internally cleaned and capped at both ends at the mill, and shall remain capped until the moment of jointing. Mill test certificates shall be provided for every consignment and shall be traceable to the installed runs. All joints shall be silver brazed under a continuous internal purge of oxygen-free nitrogen. Brazers shall be individually qualified to a recognised brazing qualification standard, qualification records shall be submitted before work commences, and joints shall be traceable to the brazer.

Terminal units and components

Terminal units shall be gas-specific and mechanically non-interchangeable, certified to ISO 9170-1, of a single connector pattern throughout the facility as specified in the schedules. Low-pressure flexible hose assemblies shall be certified to ISO 5359. Anaesthetic gas scavenging shall comply with ISO 7396-2. Certificates of conformity shall be submitted for each component type.

Alarms

Master alarm indication shall be provided at two locations, of which at least one shall be continuously staffed. Area alarm panels shall be provided for each department listed in the schedules, indicating pressure condition for every service serving that department. All alarm panels shall include a lamp and audible test facility. Alarm and sensor calibration certificates shall be provided at handover.

Testing, verification and release

The system shall be tested and commissioned in accordance with the current edition of HTM 02-01 Part A. Verification shall be witnessed and certified by a third party independent of the Contractor, appointed by the Employer, and no part of the system shall be released for clinical use until the Employer’s nominated officer has signed a certificate of clinical release supported by the gas quality test results.

Documentation

Handover shall include: as-built drawings with valve and zone identification; approved design calculations; material and component certificates; stage-by-stage signed test records; gas quality certificates; alarm and gauge calibration certificates; a valve identification schedule suitable for display at each nursing station; a preventive maintenance schedule; emergency gas failure procedures; a permit-to-work procedure for interventions on live pipework; and records of staff training. Documentation shall be provided in bound hard copy and in searchable electronic form.

That last clause is worth more than most of the technical ones. It converts the compliance file from something a contractor might produce into a contractual deliverable tied to payment.

Testing and certification sequence

Both HTM 02-01 and NFPA 99 describe a staged sequence rather than a single test, and the order matters — each stage is a gate that must be passed before the next begins. In practice the sequence for an Indian project runs:

Stage	What is being proved	Why the order matters
1. Installation inspection	Correct materials, supports, separation, labelling, identification before concealment	Once the ceiling closes, this is unverifiable
2. Initial pressure and leak test	Pipeline integrity at above working pressure, held and logged with temperature compensation	Must precede connection to source plant
3. Purge	Particulates and brazing debris swept out with dry nitrogen or oil-free air	Debris trapped now reaches a ventilator later
4. Cross-connection / anti-confusion test	Every outlet delivers only its intended gas	100% of outlets. There is no acceptable sampling rate
5. Terminal unit mechanical function and interchangeability	Probes engage correctly and gas-specific indexing cannot be defeated	Tests the safety feature that prevents the worst failure mode
6. Zone valve isolation	Each AVSU isolates exactly the zone its label claims	Verified physically, not from the drawing
7. Particulate test	The distribution network is clean at the outlet	After purge, before purity
8. Quality of gas / purity test	Purity, dew point, carbon monoxide, carbon dioxide, oil and odour, sampled at the most remote outlets	The clinical release gate
9. Alarm function test	Every area and master panel, including simulated fault conditions and plant changeover	Alarms untested at handover are usually alarms never tested
10. Flow and pressure verification at diversified load	The system performs at the demand it was designed for	Static pressure tells you nothing about performance under load
11. Final tie-in and re-test of affected zones	Connection to live systems has not compromised either side	The most common source of post-handover incidents
12. Clinical release certificate	A named person accepts the system for patient use	Without this, nobody owns the decision

The certificates a hospital should physically receive at the end: pressure and leak test records with hold data; cross-connection and anti-confusion test records covering every outlet; terminal unit function records; zone valve isolation records; particulate test results; a gas quality certificate per service from an accredited laboratory; alarm function test records; calibration certificates for alarm sensors and gauges; copper mill test certificates; component conformity certificates; the third-party verification report; and the signed clinical release certificate. If any of these are missing, the system is, from an accreditation standpoint, untested — regardless of how well it works.

Related reading

• NABH Requirements for Operation Theatres: A Practical Checklist — the documentation logic above, applied across the whole theatre complex.
• ISO 14644 Cleanroom Classes Explained for Hospital Operation Theatres — the other half of theatre compliance: air cleanliness and how it is proved.
• Medical Gas Pipeline System — scope, gases, sizing, plant options and the validation dossier delivered at handover.

Writing an MGPS tender, or reviewing bids that all claim compliance with three standards at once? Request a design and specification review and we will map your brief against HTM 02-01, NFPA 99 and ISO 7396-1 and tell you exactly where the bids differ.