Dr. Ankit SharmaDept. of Anaesthesia & Intensive

CareDr. B. S. A. Hospital, Rohini,

Central Medical Gas System

IntroductionGases and Vacuum are used in hospitals for

therapeutic purposesThe gases used in hospitals are

Medical GasesOxygenNitrous Oxide

Compressed airVacuum

IntroductionCentralized gas and vacuum supply service

is a modern system of piped supply of medical gases from a central storage area called manifold room to all delivery points in hospital

It provides a very efficient, economical and highly dependable life support service

Makes better patient care in all the areas of hospital

Functions

Supply of right medical gases at right pressure

Supply of compressed air at right pressureSupply of clinical vacuum at right pressure

50 55-psig

-(400-600)mmHg

ComponentsSource of supply: Central supply room with

control equipments and panelsDistribution system: piping Point of use delivery connections: Suitable

station outlet valves and pendantsMonitoring and control equipment and

alarms

Manifold RoomConsists of a cylinder manifold and a

control panelManifold can be of 2 banks of 2 cylinders

each or 2 banks of 20 cylinders eachControl panel: primary and secondary

pressure regulators; warning lampPressure gauges

Manifold RoomPrimary supply Secondary supply when primary supply is

exhaustedPrimary and secondary provides normal operating

supplyWhen operating supply fails, a reserve supply takes

over

Manifold RoomIn case of breakdown of control panel of

oxygen and nitrous oxide, an emergency kit ensures supply of gas through the pipes

Emergency kit comprises a regulator and high pressure tubing to a bulk cylinder and the gas is fed directly to the pipeline through a service outlet

In case the vacuum and air supply system fails, a standby motor-cum-pump is used to provide uninterrupted supply

Manifold RoomHalf of the total daily consumption of oxygen

and nitrous oxide is kept in the manifold room as reserve

Oxygen and nitrous oxide should be stored seperately from flammable gases and liquids

Storage location should be free of combustible materials

If exceeding 2,000 cubic feet storage should be outside the building

Must have generator backup, adequate ventilation, lighting and telephone communication

Control panel

Cylinder banks

NRV & TAILPIPES

PipesShould be seamless type, non-ferrous, non-

arsenic, of high quality copper tubingShould be protected against physical

damage and corrosionExposed oxygen pipelines should not be

installed in areas like kitchen, laundry and rooms where combustible materials are stored

Colour coded as per the gas content

42mm 28mm 15mm

PipesBefore pipes are erected, all pipes, tubes and

fittings should be cleaned thoroughly and washed with tetrachloride

Pipes should be blown clear using oil-free air or nitrogen

When whole system is in place, it should be subjected to a test pressure of 150 psi or 1 ½ times the working pressure for 24 hours to check, if it can withstand the pressure as well as leakages

This test, called pressure lock is done section by section

Terminal unitsGas outlets / vacuum inlet unitsConnected to source equipment through

the distribution systemLocated at actual usage pointOutlets should be gas specific and non-

interchangeableFitted with locking system and non-return

valves

Alarm systemAudio-visualMonitoring of pressureMeant to warn maintenance dept

Location and spaceGround floor in rear part Near maintenance areaSeperate enclosure for full cylinders, empty

cylinders, compressed air, vacuum supplyNo fire hazardCompresor unit in sound proof area

Story of our SystemSystem installed 2003………………functional

2009Repaired ( changed automatic control panel of

oxygen) 2013

Why the panel goes berserk repeatedly

New Automatic control panel

Old pipeline systems without alarm systems or

properly assessed

leakages. No pressure test

done.

Repeated faults in control panel in spite of replacement There is an undetctable leakage in the

pipeline downstream of the main control panelPressures were reset to higher side in order to

overcome the low pressure problems at the outlet (user ends)

Microprocessor is at the risk of damage at higher pressure settings

Solution is not possible before proper alarm systems are installed at recommended points.

Leaky valves can confuse the microprocessor to cause frequent tip-offs. And can damage it.

Key problems & there solutions in our system

Installation company: sevice contract. CMC/AMC• Electrical Backup:

Open system vs closed system

our system is open system hence both banks will open in case of power failure. Pro &

cons Alarm systems audio visual with pressure gauge importance in our current situation

Communication intercom connection and CUG phones Staffing trained technical staff attendants housekeeping Procurement of oxygen cylinders preferably from two different sources ensuring properly filled cylinders with leak free valves

Problems : when the leakage is there; it can

cause malfunction of

the control panel.

Key problems & there solutions in our system

Cylinder reserve. to ensure backup of atleast one day

preferabley 2-3 days.

Currently we have total of 76 cylinders onlyOne bank of 11 cylinders run for avg. 5 hours Approx. 55-60 cylinders/day

Recommendation is to have liquid o2 tank if demand more than one D type cylinder/hour

Reserve falls short of at least 40 cylinders.

Key problems & there solutions in our system

Problems & solutions

Leakage/

partial full

Microprocessor/ natually open

alarms

Outlet leakage

Thank You