NFPA 99C states that locations containing central supply systems, or used for storing medical gas containers, shall be ventilated to prevent the accumulation of medical gases from leaks and operation of cylinder or manifold overpressure safety devices.

 

Manifolds can be used to supply many different types of gases which displace the amount of oxygen in a closed room with no ventilation. If too much oxygen accumulates in a closed room with no ventilation, it can also be a problem. The normal concentration of oxygen in ambient air is about 21%. If a high percentage of oxygen is inhaled, the result could be oxygen toxicity. Immediate unconsciousness and possibly death may be the result if exposed to high levels of any gases, including oxygen.

 

If the total volume of medical gases connected, and in storage is greater than 3000 ft³, you must have a dedicated mechanical ventilation system that draws air from within 1 foot of the floor and operates continuously. There must also be a means for make up air to enter the room.

 

If the total volume of medical gases connected, and in storage is less than 3000 ft³, you must have two louvered openings which each have a minimum free area of 72 in². One louver must be within 1 foot of the ceiling and the other must be within 1 foot of the floor. Louvered openings are not allowed to be located in exit corridors. If the requirements for the louvered openings can not be met, mechanical ventilation must be provided.

 

That depends on the gas. Since all liquid containers would be above the 3000 ft³ threshold, we will discuss the contents of H cylinders. 3000 ft³ of oxygen would be about 12 cylinders (a 6 by 6 manifold). 3000 ft³ of nitrogen would be about 13 cylinders (a 6 by 6 manifold because they must have equal headers). 3000 ft³ of nitrous oxide would be about 5 cylinders (a 2 by 2 manifold because they must have equal headers). 3000 ft³ of Carbon Dioxide would be about 6 cylinders (a 3 by 3 manifold). Remember: these are cylinders in use and you must count cylinders in storage too.

 

Medical gas systems are an important part of every healthcare facility. Patients’ lives depend on them. Proper ventilation for indoor central supply systems keeps healthcare facilities personnel safe. If we don’t keep them safe, who will keep the patients safe? Make sure your facility has properly ventilated gas storage rooms and central supply rooms.

 

By:

 

Jay D’Agostino

Vice President of Operations

NITC/ASSE 6020 Medical Gas Inspector