An understanding of these levels is critical when designing and installing such systems.



Healthcare facilities have various levels of gases and vacuum systems. These systems are regulated by NFPA 99, also called code, the latest edition being 2005. As a member of the Technical Committee on medical gas and vacuum piping of the National Fire Protection Association (NFPA), please understand these discussions are my own and do not represent the opinions, position or interpretations of any other individual committee member, the committee as a whole or NFPA. Please refer to the actual text of the referenced standards for the exact wording.

Medical Gas And Vacuum System Levels

The term “level” represents a listing of specific systems based on the comparative degree of risk to patients and the facility in which they are installed. The levels are intended to define standards of purity, safety and reliability. They indicate intended system uses and the potential risk to a patient if this system shall fail or malfunction, and they are indicated as one to three, with one being the most critical. Alarms, gas quality monitoring and piping arrangements are outside the scope of this article.

  • Level 1 - Any dedicated, nonflammable compressed gas or vacuum system for which failure or interruption will be an immediate threat to life safety and the expectation that the patient outcome would result in death or permanent injury. The official definition is “imminent danger of morbidity or mortality.” A Level 1 gas system must be installed in critical areas and also serve patients who could be provided with mechanical ventilation or assisted mechanical ventilation. The patients are dependent upon such systems for critical life support while undergoing or recovering from invasive diagnostic, treatment or surgical procedures.

    The Level 1 vacuum system serves any station inlets installed in critical-care areas, including waste anesthesia gas disposal, and provides medical/surgical support for the patient population undergoing or recovering from invasive diagnostic, treatment or surgical procedures. This level includes the alarms, operating controls, gauges, etc. High-pressure compressed gases over 160 psig used to serve pneumatic devices that are used for invasive procedures are Level 1, which also includes instrument (support) air that is used as a replacement for nitrogen. The supply and alarms must be redundant.

     

  • Level 2 - Any nonflammable patient gas distribution system in which patients are not dependent upon such systems for critical life support and are not provided with mechanical ventilation or assisted mechanical ventilation. The failure of this level of system may result in death or permanent injury. This level is used where a patient is at manageable risk of morbidity or mortality if the system fails.

    This will serve any patient who is dependent upon the piped medical gas and vacuum system for well-being, and for recovery from invasive diagnostic, treatment or surgical procedures, where a bottled gas could be substituted quickly for the failed service. This includes support air. The source supply, equipment and alarms can be simplex. They must not be connected to Level 1 central systems and are not permitted to be used in hospitals. The occupancy to be served and the function of that occupancy where Level 2 is installed is different from other occupancies in a hospital.

     

  • Level 3 - These systems are considered low risk to a patient and will be found where interruption of the piped systems would allow termination of a procedure that would not place the patient at risk of mortality or conditions that would lead to death. Patients are not dependent on compressed gas or vacuum. Such systems will be found in facilities such as dental offices and clinics. This is any nonflammable patient gas at a pressure of 160 psi (1100 kPa) distribution system or less providing a source of power for orthopedic, pediatric and plastic surgery devices and for dental services.

    The vacuum system can be either wet or dry and is used predominately for removal of liquids from any treatment area, and from the oral cavity. Alarms and supplies need not be redundant. The systems installed must not supply more than two adjoining treatment facilities.

     

  • Laboratories - Although no longer in the piping section, it is a practice to require that where the eyes or bodies can be exposed to injurious or corrosive material, fixed emergency eyewash and showers are provided. Natural gas and propane systems must conform to NFPA 54, Fuel Gas Code, and NFPA 58, Liquefied Petroleum Gas Code.


    • Compressed Air

    Air is divided into the following categories (levels):

  • Level 1 low-pressure medical/surgical (patient) compressed air is used for life support and human consumption. Level 1 compressed air is distributed at a pressure of between 50 and 55 psig (340 and 375 kPa) and is used primarily for patient inhalation, anesthesia purposes and to power ventilators. It is a requirement of the code that the compressor used as a source for the medical/surgical air system be dedicated and not used for any other purpose.

     

  • Level 1 support gases are high-pressure compressed gas systems of air or nitrogen NF distributed at 160 psig or higher. This is used to supply gas-supplying pneumatic tools for procedures, articulating arms, columns and other devices not used for patient care. If a compressor is used as the source, the compressor must be redundant and not used for any other purpose.

     

  • Level 2 low-pressure medical/surgical (patient) compressed air for medical/surgical (patient) is permitted when no patient has mechanical ventilation or assisted mechanical ventilation. They cannot be used for life support and the system is completely stand-alone and separate from other occupancies in the building. Level 2 is similar to Level 1 except for redundancy.

     

  • Level 2 support gases at a pressure more than 160 psig are similar to Level 1 requirements except for redundancy.

     

  • Level 3 patient low-pressure compressed air and vacuum is permitted if the patient population is not dependent on the gas or vacuum for any life support. Level 3 can be used if supplying no more than two treatment offices and for dental facilities. Compressed air in facilities outside hospitals for dental use is often distributed to dental chairs at a pressure of between 80 and 100 psig and is reduced to 30 or 50 psig locally, depending on specific uses. It is also used to drive dental tools and other pneumatic devices.


    • Nitrogen

    Nitrogen is used primarily to power pneumatic devices in surgical and medical suites. When used to power pneumatic tools, nitrogen is centrally distributed at pressures between 20 and 250 psig (140 and 1725 kPa), depending on the specific tools used. Although mostly distributed at 160 psig or higher, the system must conform to standard CGA NF.

    Nitrogen is also used for inhalation therapy where mixed gases closely matching natural air proportions are desired. It is not unusual to have two separate pressure systems in some facilities. Often, a dedicated nitrogen cylinder (or bank of cylinders) is installed at each location with the required controls and regulator. Nitrogen is considered a Level 1 gas.



    Vacuum Systems

    Vacuum is a system that uses air below atmospheric pressure. There is no requirement that any level of vacuum service be a dedicated one. Where there is only one vacuum source for a facility, the vacuum system for a laboratory must connect directly into the receiver tank separate from the medical/surgical system through its own isolation valve and fluid trap located at the receiver.

  • Level 1 medical/surgical vacuum air, sometimes referred to as patient vacuum systems, is used in operating rooms, intensive care areas, medical and surgical suites and patient rooms to assist in the removal of fluids. The operating pressure of this system is in a range of 15-20 inches of mercury (in.hg.) vacuum.

     

  • Level 1 waste anesthesia gas disposal vacuum systems are used to remove waste anesthesia gases from anesthesia locations by directly connecting to a dedicated outlet on anesthesia machines. The operating pressure of this system from a pumped source is in a range of 15-20 in.hg. vacuum.

     

  • Level 2 medical/surgical vacuum air is used when the system does not serve patients on life support systems, but the patients are dependent on this system for recovery and well-being. The operating pressure of this system from a pumped source is in a range of 15-20 in.hg. vacuum.

     

  • Level 3 dental vacuum air is used for removal of fluids and solids from the mouth produced by dental procedures and drills that cool with water. These systems are generally wet/dry type systems where the vacuum pipe carries a combination of air and fluid to a separator and the fluid is removed and disposed of into the sanitary drainage system. The operating pressure of this system is in a range of 8-17 in.hg. vacuum.


    • Definition Of Healthcare Facilities

    Healthcare facilities include hospitals, nursing homes, medical and dental offices, and clinics. These facilities fall into two general categories: short-term (acute care) and long-term care. Short-term is considered the typical acute care surgical/medical-type hospital, as well as clinics and outpatient treatment care facilities not requiring overnight stays, such as podiatry and plastic surgery.

  • Hospital - A hospital is defined as a building or part thereof that is used for medical, obstetrical, psychiatric or surgical care on a 24-hour basis for four or more patients. The hospital includes general hospitals, mental hospitals, TB hospitals, children’s hospitals, etc., and any facility providing inpatient care.

    1. Medical/surgical compressed gases and vacuum systems for direct patient care, pneumatic devices or supplying mechanical or assisted mechanical ventilation equipment shall conform to Level 1.

    2. Waste anesthesia gas disposal (WAGD) systems shall conform to Level 1 requirements and may be produced by either a dedicated system or connection to the medical/surgical vacuum system.

    3. High-pressure support gases (nitrogen or instrument air) for pneumatic devices, tools, etc., shall be Level 1, and also may be used for laboratory purposes if appropriate. They shall not be used for respiration.

    4. Level 2 systems are not permitted.

    5. A Level 3 gas (nitrous oxide and oxygen only) and vacuum system for dentistry shall be permitted if not connected to the hospital’s Level 1 central system source. The gas systems shall not be used for patient or staff ingestion. Existing systems are permitted to be used, providing that they do not constitute a hazard to life as determined by the local authorities.

     

  • Nursing home - A facility providing long-term nursing care and housing on a 24-hour basis for patients who, because of physical or mental incapacity, may be unable to provide for their own needs without the assistance of another person. This facility includes nursing and convalescent facilities, skilled nursing homes, intermediate care facilities and infirmaries with homes for the aged. Piping systems, if installed, shall conform to the following levels:

    1. Medical gas and vacuum systems, if provided for patients with mechanical or assisted mechanical ventilation considered critical life support, shall conform to Level 1, as well as any gas connected to Level 1 sources or distribution piping.

    2. Where patients are not dependent on medical gas or vacuum systems at any time for critical life support, they shall conform to Level 2, if provided.

    3. All other systems, if provided, shall conform to Level 3.

     

  • Limited care facility - A facility used on a 24-hour basis for the housing and care of four or more persons who are incapable of self-preservation due to illness, accident or mental retardation or chemical dependency. Piping systems shall conform to the following levels, if installed:

    1. Where patients are provided mechanical or assisted mechanical ventilation, gas and vacuum systems, these systems shall conform to Level 1.

    2. They shall meet Level 2 if they do not meet all of the above conditions.

     

  • Other healthcare facilities - “Other” facilities, or portions thereof, provide diagnostic and treatment services to patients in healthcare facilities other than that provided in hospitals, nursing homes or limited-care facilities. This “Other” category is intended to encompass all other facilities without the need for specifically naming them, which in the past has resulted in misinterpretation and misapplication of provisions of this standard. It includes small outpatient facilities and medical and dental offices. Piping systems shall conform to the following levels, if installed:

    1. Medical compressed gases and vacuum systems supplying mechanical or assisted mechanical ventilation equipment and a WAGD system shall conform to Level 1. If general anesthesia is given, Level 1 systems are required.

    2. Where patients are not dependent on medical gas or vacuum systems at any time for critical life support, they shall conform to Level 2, if provided.

    3. All other systems, if provided, shall conform to Level 3.