Medical Gas Pipeline Systems in Pakistan: HTM 02-01 Design Guide

A hospital can survive a broken lift or a leaking roof for a day. It cannot survive a failure of its oxygen supply. Medical gas pipeline systems in Pakistan carry oxygen, medical air, nitrous oxide and vacuum from central plant rooms to every bed head, operation theatre and ICU bay, and they must work without interruption for the life of the building. This guide explains how a medical gas pipeline system (MGPS) is designed, built, tested and maintained to the UK Health Technical Memorandum HTM 02-01 or the American NFPA 99 code, and what hospital owners in Pakistan should check before they sign off a design or a contractor.

Why Medical Gas Engineering Deserves Special Attention

The COVID-19 pandemic showed hospitals around the world, including in Pakistan, how quickly oxygen demand can outgrow a pipeline that was sized for normal use. Wards that had been designed for occasional oxygen therapy suddenly had most beds on high-flow oxygen at the same time. Pressure dropped at the far ends of the network, and some hospitals had to ration supply.

That experience changed how owners and engineers think about medical gases. A well-designed MGPS is not a set of copper pipes added at the end of a project. It is a life-support system that has to be planned with the clinical brief, the structure, the HVAC and the electrical design from the first stage. It is also one of the services most closely checked during licensing inspections, so mistakes are expensive to fix after handover.

The Medical Gases a Hospital Pipeline Carries

Not every facility needs every gas. A day-care clinic may need only oxygen and vacuum, while a tertiary hospital with cardiac surgery needs the full set. The clinical brief decides which services go where.

HTM 02-01 vs NFPA 99: Which Standard to Follow

Pakistan does not have a national code written specifically for medical gas pipelines. Designers therefore follow an international standard, and the choice usually depends on the client, the consultant and any international funding or accreditation targets. What matters most is that one standard is chosen at the start and followed consistently, from design through testing.

Mixing standards, for example HTM pipe sizing with NFPA outlets bought separately, is a common source of problems. Equipment, testing procedures and documentation should all match.

Supply Sources and Plant Rooms

Oxygen supply: three independent sources

A core principle of HTM 02-01 is that oxygen must come from three independent sources, often described as primary, secondary and reserve (or emergency) supply. In Pakistan the common arrangements are:

• Liquid oxygen (VIE tank) as the primary source for medium and large hospitals, refilled by tanker.
• PSA oxygen generator plant as a primary or secondary source, especially where tanker supply is unreliable.
• Cylinder manifolds with automatic changeover as secondary or reserve supply.

Where PSA plants are used, the oxygen purity they produce and its suitability for each clinical use should be confirmed with the clinical team and the regulator. Space for tanker access, safety distances around liquid oxygen tanks and ventilation of manifold rooms must be shown on the site plan from the beginning.

Medical air and vacuum plant

Compressors and vacuum pumps are installed as duplex or multiplex sets, so the system keeps working when one unit fails or is being serviced. Air intakes must draw clean outdoor air away from vehicle exhausts, generator flues and vacuum discharges. Vacuum exhausts must discharge safely outside, away from windows and air intakes.

Power and resilience

All medical gas plant, alarms and controls must be on essential (generator-backed) supply. Given load-shedding in many parts of Pakistan, this is not optional. The electrical design should be coordinated with the MGPS design early.

Pipeline Design and Installation

Sizing and diversity

Pipe sizes are calculated from the number of outlets in each department, the expected flow at each outlet and a diversity factor that reflects how many will be used at the same time. After the pandemic, many owners now ask designers to allow extra capacity for surge conditions in ICUs and wards. Pressure drop to the furthest outlet must stay within the limits set by the chosen standard.

Materials and workmanship

• Medical-grade, degreased copper pipe and fittings, delivered capped and cleaned for oxygen service.
• Brazed joints made with an inert gas purge inside the pipe to prevent oxide scale.
• Pipes labelled with gas name and flow direction at regular intervals.
• Separation from electrical services and protection from heat and mechanical damage.
• Installation only by trained medical gas technicians, not general plumbers.

Valves, zones and terminal units

The network is divided into zones so that a fault in one area can be isolated without cutting supply to the whole hospital. Area valve service units (AVSUs) are placed at the entrance to each department, usually near the nurse station where staff can reach them quickly. Terminal outlets are mounted on bed-head trunking, ceiling pendants in theatres and ICUs, or wall panels, and they are gas-specific so that an oxygen hose cannot be plugged into an air or vacuum outlet.

Alarm and Monitoring Systems

Alarms tell staff that something is wrong before patients are affected. A typical MGPS has three levels:

• Plant alarms at the plant room for faults such as low cylinder bank, compressor failure or dryer fault.
• Central or emergency alarms at a continuously staffed location, such as the telephone exchange or security room.
• Area alarms in departments such as ICU and theatres, showing high or low pipeline pressure for each gas.

Modern systems can also send alarm signals to the building management system, so the engineering team sees faults on a central screen. Alarm locations should be agreed with the hospital’s operational team, not decided by the installer.

Testing, Commissioning and Handover

No MGPS should be put into clinical use until it has been fully tested and certified. Testing is detailed and must be witnessed and recorded.

After handover, the hospital needs a written operational policy for the MGPS, trained staff, and a planned maintenance contract for plant, valves and alarms.

Common Mistakes in Pakistani Hospital Projects

• Sizing the oxygen system only for normal demand, with no allowance for surge or future beds.
• Using non-medical copper pipe or brazing without an inert gas purge.
• Placing zone valves where staff cannot find or reach them in an emergency.
• Leaving tanker access and liquid oxygen tank safety distances out of the site plan.
• Buying outlets from one standard and alarms or pipe sizing from another.
• Opening wards before the system is tested and certified.

Medical gases are closely linked with ventilation and fire safety. Our guides to hospital HVAC and infection control and hospital fire safety design explain how these systems are coordinated.

Frequently Asked Questions

Conclusion

A medical gas pipeline system is one of the few building services that directly keeps patients alive. In Pakistan, where power cuts, supply disruptions and rapid demand changes are real risks, the MGPS needs resilient sources, careful sizing, clear zoning and rigorous testing. Choosing one standard, HTM 02-01 or NFPA 99, and following it from concept to handover is the surest way to a safe system. ACCO designs and builds medical gas systems as part of its hospital design and construction services, with every system priced through an itemised BOQ.