How to interpret NFPA 99 medical gas, electrical changes

NFPA 99: Health Care Facilities Code identifies some new ways to specify medical gas and electrical systems

By Sean C. Hu and Kenneth A. Frazier June 24, 2021


Learning Objectives

  • Introduce 2021 edition of NFPA 99: Health Care Facilities Code.
  • Identify and apply solutions for important medical gas and electrical system design and construction topics.
  • Examine practical approaches to NFPA 99 requirements.

NFPA 99: Health Care Facilities Code has become a prevalent document applied to more buildings than ever as health care system strategies migrate from traditionally large centralized facilities to smaller distributed facilities, ambulatory surgical facilities, medical office buildings and clinics integrated closer to patient neighborhoods. The need for a decentralized health care environment has been further amplified by the impact of COVID-19. Simply, the model of health care delivery is changing.

The migration is a business strategy to increase efficiencies and locate facilities closer to communities they serve. The construction and maintenance cost savings can be significant for outpatient procedures and health care activities. The progression of change makes it a really exciting period of time for patients, health care providers and health care engineers.

Health care systems are delivering health care in a larger variety of facility types and occupancies making the identification of applicable codes, guidelines and standards more challenging for professional health care architects and engineers. Design professional and building officials continue to reference three industry recognized and commonly adopted codes including the International Building Code, NFPA codes and standards and the Facilities Guidelines Institute.

NFPA 99 is an industry-recognized code adopted by a majority of jurisdictions in the United States and also internationally, referenced by authorities having jurisdiction and a valuable resource for architects and engineers with a professional heath care design focus with the exception of residential home care and veterinary medical care.

Per NFPA 99 Article 3.3.73, a health care facility is defined as “buildings, portions of buildings or mobile enclosures in which human medical, dental, psychiatric, nursing, obstetrical or surgical care is provided.” Home care, where NFPA 99 may not apply, is defined by medical service provided in residential settings. Review of these definitions with the health care organization is recommended if it’s unclear how a facility should be defined.

Adoption of IBC, NFPA and FGI varies state-by-state and often linked with regulatory bodies such as Centers for Medicare & Medicaid Services and The Joint Commission. Health care facility compliance is commonly required for insurance and CMS reimbursement of patient medical costs.

Health care organizations, design professionals and code officials all have a common goal to provide a safe environment for the staff and patients in these facilities. A clear understanding of the applicable state and federal regulatory bodies governing the health care system and facility is a roadmap for compliance, health care licensure and patient standard of care.

Medical gas updates

The 2021 edition of NFPA 99 introduces several small changes and clarifications. NFPA 99 focuses the importance of the role of the responsible facility authority as the designated on-site authority for medical gas systems. It also expands on hyperbaric chamber scope, provides additional direction on decommissioning clinical spaces, clarifies cryogenic fluid requirements to align with NFPA 55: Compressed Gases and Cryogenic Fluids Code, amends procedures for dealing with flammable materials in operating rooms and adds fire protection of heliports to Chapter 16.

Another substantial addition to the code this year is a new section on health care microgrids in Chapter 6. This addition is likely the result of an increased number of health care organization taking a closer look at on-site grid redundancy and alternative power generation sources.

Chapter 5: Gas and Vacuum Systems, has evolved over several editions with the goal to define standards and provide guidance for patient safety at a variety of different facility, treatment and occupancy types. The identifying and evaluation of previous construction, maintenance and operational practices is fundamental in the development and refinement of the standards.

As an example, health care systems are required to designate an on-site RFA to manage the operation, maintenance, inspection and work permits of the medical gas, vacuum and waste anesthetic gas disposal systems for a specific facility (NFPA 99 Article The qualification of the RFA is described in NFPA 99 Article The clarified intent of the RFA is to ensure an active participant, rather than an observer, in the design and construction process.

As a person that is qualified to interpret, implement and advise on the code, it will simplify the certification process required for the system before use by patients. Identification and resolution of potential code conflicts as a result of systems that have been designed and constructed under previous versions of the code during the design process can eliminate delays in certification once construction is complete. This is important to the design engineer, as it provides a valuable resource for the interpretation of some of the code requirements as they relate to the individual facility. The RFA manager addresses the concern to make knowledgeable practitioners available for guidance and better understanding in each health care facility.

The 2021 edition of NFPA 99 provides a clarification of the technological changes incorporated into the 2018 edition. In the 2018 edition, dental gas and vacuum system requirements were moved to Chapter 15. These systems predominate represented Category 3 systems. The COVID-19 pandemic has reinforced the need for the requirements and heightened awareness to improve and enforce them.

Another change includes the addition of alarm wiring for the emergency oxygen supply connection. The alarm wiring connects the EOSC box and the master alarm panel in the event that the EOSC connection is required for sustained facility operation. Several system details and performance criteria need to be addressed for each installation including:

  • Termination location of low-voltage cabling.
  • Alarms to display.
  • Alarm cabling monitor.
  • Treatment of signal during normal and EOSC use.

The 2021 edition provides an exemption of the fire rated wall construction requirement for spaces without oxidizing gases (oxygen and nitrous oxide). Nitrogen has also been relocated to the support gas section.

Several smaller changes clarify important requirements for medical gas systems. The following is a consolidated summary of the smaller changes:

  • Chapter 14 clarifies the responsibility of hyperbaric gas systems by the hyperbaric technical committee.
  • New labeling requirements are defined for medical air intakes and vacuum exhausts and relief valve vent. The dual-use waste anesthesia gas disposal/medical vacuum piping systems and alarm panels both shall be labeled. The use of different identifying colors valves, outlets and alarms are standard industry practice and now required.
  • New Article (9) adds a minimum working pressure for valves equal to or greater than the relief valve protecting the system.
  • New Article adds requirements for check valves.
  • New Article adds a minimum size for waste anesthesia gas disposal piping of ½ inch nominal pipe size.
  • New Article requires medical gas outlets in areas no longer being used as patient care spaces be decommissioned or removed.
  • New Article 5.3 clarifies Category 3 requirements and is only applicable to medical facilities with minimal sedation.
  • Article revised the phrase “as long as” to “unless” to clarify that an existing system can be used without AHJ action upon adoption of a new code. Previously, the AHJ had to actively approve use of the existing system.
  • Article associated with the auxiliary source connection was relocated to Article
  • New Article indicates alarm switches and sensors remain accessible for service, testing and removal when applicable.

Medical gas piping

Medical gas systems and outlets are provided for patient care. The code promotes practices to prevent contamination of the medical gas piping system. An example of improper use of medical gas systems includes outlets located in facility maintenance spaces used for tool and equipment blow down/off or pneumatic supply to operated doors and temperature control components.

The designer/installer should be conscious of spaces to avoid medical gas piping routing including kitchens, stairwells, elevator shafts and elevator machine rooms, areas with open flames, near electrical service equipment greater than 600 volts and areas prohibited under NFPA 70: National Electrical Code.

All medical gas outlets are required to be served through a local zone valve box. Existing health care facilities may have examples of vacuum outlets not piped through a local zone valve box. New and remodeled medical gas outlets need to be piped through a local zone valve box. The revision can be a concern with limited renovation projects when not all of the practical gas outlets and rooms associated with a zone are not being renovated. A long-term owner renovation plan commitment and AHJ approval could be an interim solution.

Zone valve boxes require careful coordination between the engineer and the architect. The valve boxes need to remain accessible to staff, clear of obstructions and not located behind normally open/closed doors. The piping associated with the valve box also will require a significant portion of the adjacent concealed wall stud space, limiting availability to other systems.

The placement and visibility of valves and notification alarm panels can be a challenge within many existing facilities. Renovations and expansions commonly introduce potential long-term concerns disguised as practical function decisions during the renovation. The addition of this shows the concern and intent of addressing these issues. Maintained access to valves, notification alarm panels, documented operating procedures and staff training need to be followed as follows:

  • Foreign items shall not be placed in front of or affixed to any alarm panel that would restrict the view or diminish the sound of the alarm.
  • Valves in secured areas are to be specified as follows:
    • The valve is visible from the intended operator’s staffing position or work area.
    • The valve is operable with no more than ordinary aids, such as a ladder.
    • When the valve is provided with security hardware, such hardware is visible and readily removeable when needed.

Electrical systems updates

The electrical systems shall be tested and site accepted, and an electrical preventive maintenance program is required for all Category 1 and Category 2 classified spaces and systems, per Article 6.9.1. The article defines the requirements for inspections, testing and service of electrical equipment. The maintenance of compliance records shall be maintained for a minimum of five years. Table identifies inspections, testing and maintenance intervals for specific electrical equipment.

New Article 6.10: Microgrids is an intriguing new section. Health care microgrids may be used as a portion or the entire emergency power supply system and serve a single building or a campus of several buildings.

A microgrid is a an integration of one or more energy-generation sources acting independently or in parallel with the utility company supply, and serves a group of interconnected loads (buildings, structures, etc.). The microgrid load has a clearly defined boundary, which may encompass a single building or multiple buildings and structures. The boundary may encompass both health care and nonhealth care facilities.

Article 6.10 provides various design requirements for microgrids to be properly implemented in reliable system for facility power and complimentary of the emergency operation plan. The microgrid must be capable of operation upon failure of the normal utility service, include controls and provided a minimum capacity of 90 minutes when used to serve the life safety branch of the essential electrical system.

The design team should review these sections carefully when developing a microgrid for health care facilities. Microgrid power sources may include renewable energy sources, on-site power generation and combined heat and power plants.

Coordinating electrical systems

Impactful electrical NFPA 99 topics include the appropriate configuration of the ESS and the identification of wet and anesthetizing patient care areas. These items can have a significant implication on the design and construction requirements of the project and need to be considered early in the planning phase.

These topics are managed by early engagement between the design team, owner, health care providers and designated RFA. The existing Level 1 EES represents a finite resource of emergency power, distribution and potential availability of every branch in some areas of the facility. Larger renovations and additions can quickly require the expansion of the EPS (e.g., generators) and emergency power supply system (e.g., transfer switches, distribution equipment) and other branch panelboards.

The classification of risk categories needs to be universal between all involved stakeholders, align with the activities of health care providers using the spaces, align with the facility risk management plan and be clearly shared with the AHJ and other regulatory organizations.

Operating rooms are commonly classified as wet locations with invasive procedures being performed unless otherwise classified by the owner’s designated health care facility governing body. The classification of multiple other patient care and medical procedure spaces can be difficult to classify properly without an understanding of the intended use by health care providers.

Risk categories

The risk category of a patient care area drives many of the medical gas and electrical requirements for the space. The decentralization of health care facilities and evaluation of risk categories introduces a requirement to define the exact functions, activities and medical care planned to be offered in each space and facility. Related to medical gas and electrical systems, there are four risk categories and four system categories defined in NFPA 99.

Risk categories: Activities, systems or equipment shall be designed to meet Category 1 through 4 requires as detailed in this code.

  • Category 1: Activities, systems or equipment whose failure is likely to cause major injury or death of patients, staff or visitors shall be designed to meet Category 1 requirements as detailed in the code.
  • Category 2: Activities, systems or equipment whose failure is likely to cause minor injury of patients, staff or visitors shall be designed to meet Category 2 requirements as detailed in the code.
  • Category 3: Activities, systems or equipment whose failure is not likely to cause injury to patients, staff or visitors, but can cause discomfort, shall be designed to meet Category 3 requirements as detailed in the code.
  • Category 4: Activities, systems or equipment whose failure would have no impact on patient care shall be designed to meet Category 4 requirements as detailed in the code.

System categories: Four levels of system categories are defined in this code, based on the risk to patients and caregivers in the facilities (see Table 1).

The system category applies to electromechanical systems and not intended to consider intervention by caregivers. A risk assessment should be conducted to evaluate the risk to patients, staff and visitors.

For medical gases, surgical users often desire oxygen, medical air, surgical vacuum, waste anesthesia gas disposal and nitrous oxide (N2O) in the suite. These systems can be provided independent of the classification of the surgery space. However, the use of N2O often triggers greater attention by design professionals and AHJs in regard to the acuity of care and risk category of the space.

When evaluating appropriate risk category, the level of sedation is of upmost importance. In a Category 1 space, general anesthesia or deep sedation is allowable. To be classified as Category 2 or 3 space, only moderate sedation, minimal sedation or no sedation is performed. Deep sedation and general anesthesia are not permitted in a Category 2 or 3 space.

Exploring the code language, the requirements for Category 1 and 2 are similar when it comes to medical gas systems. The sections covering Category 2 installations often directly reference the requirements spelled out for Category 1. Outpatient facilities such as ambulatory surgery centers or imaging facilities must pay close attention to the level of sedation used in the spaces, as this can change the requirements and categorization of the space.

Other outpatient functions such as endoscopy, physical therapy or rehabilitation centers can often be classified as Category 2. Infrastructure, such as the source and piping system, is similar for the two risk categories with the major exception being the need for master alarm panels located in one location versus two.

Clinical input is important in the determination of the risk category. Health care facilities need to properly evaluate the level of sedation needed for the procedure or the application and not leave it up to the design engineer. Instances requiring deeper levels of sedation may be necessary for MRI or CT scans for pediatric patients. Unless these are preformed within a hospital, the medical gas system may not be technically suitable for the intended use.

The importance of the clarification of the RFA’s role and qualifications in NFPA 99-2021 will help the design engineer determine compliance path by providing a stakeholder on the owner side who understands the facility operations. Taking the responsibility for the evaluation of the procedural requirements and levels of sedation from the designer and making it a facility requirement is a key shift in responsibility. Having the right people involved early in the decision-making process can save time and prevent delays and costly change orders.

Implementing NFPA 99

There are instances when a consulting engineer interprets a code requirements one way during design and the medical gas certifier will interpret it differently during inspections resulting in a noncertified system. The medical gas systems code language has known “gray” areas that exist and have yet to receive further clarification. The recommendation to perform a pre-construction review of system design with the AHJ should any unclear requirements have design or construction related implications to a project.

Still important in 2021 is for the installing contractor to perform initial pressure tests, witnessed by an American Society of Sanitary Engineers 6020 inspector, ASSE 6030 verifier or the AHJ. The labeling and valve tagging for all concealed components and piping distribution shall be inspected. The initial pressure test involves join testing at 150 pounds per square inch gauge and should be performed before wall close-in. It is standard practice for the installing contractor to perform the test. However, the requirement for the test to be witnessed is relatively new. Nobody wants to have to open finished walls because medical gas piping was not properly inspected.

The health care facility electrical designer should review NFPA 99 Chapter 6 in its entirety. It is a necessarily robust chapter, with each section containing important information that will apply to health care facility projects. We’ve found that AHJs are becoming increasingly familiar with and sensitive to the NFPA 99 electrical requirements. Special attention to interpretations specific to each jurisdiction can help the design team, construction team and reviewing bodies align.

The code still outlines specific requirements for electrical device quantities and circuiting for patient care locations. Receptacle requirements can be found in Section At patient bed locations, the normal power receptacles must be fed by not more than one normal power distribution panel while the critical power receptacles are permitted to be fed by more than one critical branch distribution panel, per Section

Lighting systems serving patient care areas with deep sedation and general anesthesia require one or more battery-powered lighting units. The intent of this code is to provide lighting to cover the power gap between loss of normal utility service and activation of the EES.

The code retains the previous requirements for locations involving wet or invasive procedures. The requirements protect patients from electrical shock by:

  • Limiting the potential for ground fault.
  • Providing ground fault circuit interruption.

Applicable patient care spaces include operating rooms, catheter labs and other special patient care spaces involving invasive procedures or subject to fluids. The code allows two compliance paths including GFCI or line isolation panelboards with isolated power representing the industry standard practice.

Articles 6.4 and 6.5 clearly define the requirement of any space with a risk Category 1 or 2 to be served by an EES. Risk Category 3 or 4 spaces to not require the same system.

Table 1 summarizes the EES requirements for the various types. Types 1 and 2 EES trigger a unique set of electrical requirements, most importantly an EES power source classified as Type 10, Class X, Level 1 Emergency Power Supply (per NFPA 110: Standard for Emergency and Standby Power Systems).

The design team needs to work closely with health care providers and designated health care facility governing body to properly classify and design patient care spaces. A risk assessment of each space should be provided by the designated by the health care facility governing body.

Author Bio: Sean C. Hu is a vice president at WSP. Hu leads engineering teams with a focus on health care and science technology projects. Kenneth A. Frazier is a vice president at WSP. Frazier has completed hundreds of new construction, renovation and infrastructure replacement projects, almost exclusively for health care clients.