How to apply NFPA 99 in the design of health care facilities

Learning Objectives

The design of a health care facility requires engineers to “place the public welfare above all other considerations,” as defined by the engineer’s creed. While this is equally important in the design of every project, health care facilities are unique in that patients and medical staff with a wide variety of age, health and physical ability are brought together into a common environment.

Because occupants of hospitals are immunocompromised or are heavily reliant on others for care, these facilities require a focus on life safety, system reliability, infection control and many other considerations that may not be present in other facilities.

There are many codes and standards that engineers of health care facilities use to establish minimum requirements for the design including NFPA 99: Health Care Facilities Code, ASHRAE 170: Ventilation of Health Care Facilities and state hospital licensing regulations.

NFPA 99 “establishes criteria for levels of health care services or systems based on risk to the patients, staff or visitors in health care facilities to minimize the hazards of fire, explosion and electricity.” Some of the systems referred to within the code include electrical power, fire alarm and both combustible and noncombustible medical gases.

Health care facilities that participate in federal reimbursement programs are required by Centers for Medicare & Medicaid Services to meet minimum facility condition requirements to maintain their reimbursement status. Compliance with the 2012 edition of NFPA 99 is essential to maintaining this status.

Applying the requirements of NFPA 99 are crucial to the health and safety of the patient as well as the system or facility providing the care. While the purpose of the code is clear, interpretation and application of details within the code are often viewed differently by engineers and code authorities. NFPA, as an organization, accounts for this by holding a public forum on each edition release of the code to clarify some of these issues.

Simulation centers

Health care providers are using simulation centers in their facilities to provide realistic training to medical staff. The purpose of a simulation center depends on the service being provided. Common applications include using a simulation center to administer hands-on training for staff on new or changing procedures and using the space to evaluate the need for new medical equipment.

A simulation center can be used to simulate interventional imaging procedures, surgery, labor and delivery procedures and many other applications. The size and location of these simulation centers varies depending on the intent of the simulation. These simulation centers may be located in the same building or on the same floor as the services that they are simulating, which has led to design interpretation issues with code authorities.

The health care provider often wants to construct the simulation center as an exact replica of the procedure it is simulating. The benefits of this to the owner are obvious as they will be able to use equipment, prepare procedures and have a functioning space, which allows an exact simulation of how they will provide care to their patient in a real-world application. Designing the simulation centers in this manner is costly to the owner and has sometimes posed a conflict with adopted editions of the NFPA 99 before 2018.

NFPA 99-2012 Section 5.1.3.5.2: Permitted Locations for Medical Gases states that medical gases designed to serve patient care spaces are only permitted to be installed where the gases will be administered “under the direction of licensed medical professionals.” There are five specific purposes listed for the installation and use of medical gases.

The concern expressed by NFPA related to this section of the code is that medical gases could be serving a space that is outside the control of a medical professional that has the proper training on the operation of these gases. NFPA intended this section of the code to ensure that these systems do not fail or become contaminated while under the control of an untrained user. This presents a difficult challenge for the engineer designing a simulation center to provide an accurate simulation of these systems in a space that is not considered acceptable for medical gases.

A design strategy that has been used that satisfies the needs of the facility and NFPA is to simulate the medical gases being delivered to the space. For example, in a simulation room requiring medical air, medical vacuum and oxygen, a dedicated air compressor could be provided to deliver nonmedical compressed air to the oxygen and medical air outlets installed within a space.

Medical vacuum systems are not usually held to the same regulations as oxygen and medical air systems. This is because the NFPA 99 does not specifically mention it in its permitted locations. The description does mention all other patient medical gases, therefore medical vacuum can sometimes be left up to the discretion of the code authority. Because of this, the medical vacuum required for the simulation center could be served from the hospital’s main medical vacuum system provided it has a dedicated zone valve to control the simulation space or be served from a dedicated medical vacuum pump.

It is recommended that additional signage be provided near the medical gas outlets that indicates to the user which gases are being provided in the simulated environment so that future renovations do not allow for the space to be used for patient care. The same could be said for the electrical systems and the entire simulation center itself.

This design strategy has been an acceptable method for engineers to address the code requirement, but it does present another unique challenge that should be paid attention to during design. It is common for these simulation centers to have the same medical gas outlets, booms and pedestals installed so that the end user is familiar with the operation of this equipment. It is important for the owner to discuss the use of simulated gases with the manufacturer of the various medical gas outlets to ensure the warranty on this equipment is maintained with an alternative use or gas.

It is common to have these strategy discussions for simulation centers being designed in accordance with NFPA 99-2012, however in NFPA 99-2018, the design of simulation centers was addressed. NFPA 99-2018 Section 5.1.3.5.2 includes the same verbiage as the 2012 version, however a sixth item was added to the allowable spaces that states “simulation centers for the education, training and assessment of health care professionals.”

By adding simulation centers as a permitted location for medical gases, NFPA recognizes that a true simulation of these systems is essential to the training of medical staff. It is important for design teams to understand which version of the NFPA 99 has been adopted so that proper application for these simulation centers can be applied.

Wet procedure locations

What constitutes a “wet procedure,” and where these occur in a health care facility has long been a discussion among design teams. The term “wet procedure location” is referenced seven times in NFPA 99, with cross references to NFPA 70: National Electrical Code. The premise behind this term is to reduce the risk of electrical shock to a patient in a treatment area that is a wet environment. With such an important safety measure to consider and with such a broad scope, it is apparent why this code language is so heavily discussed.

Who defines where a wet procedure is performed and who is responsible for maintaining design consistency in a wide variety of services, providers, etc.? NFPA 99-2012 Section 1.3.4.3 states that it is the “responsibility of the governing body of the health care organization to designate wet procedure locations.” This implies that officials within the health care organization have authority to define a wet procedure and where those procedures occur. These officials could be the risk management, the chief nursing officer, etc. The 2018 edition of NFPA 99 has revised the term “governing body” to “health care facility governing body” to provide clarity on these responsibilities.

The owner of the facility should provide input to aid the design team in determining what spaces should be should be designed with additional protection based on the specific procedures that will be performed. Further clarification is provided in NFPA 99-2012 Section 3.3.184 where it is stated that a wet procedure location is “where a procedure is performed that is normally subject to wet conditions while a patient is present.” Per NFPA, this does not include routine housekeeping procedures where a wet environment might be present in the absence of a patient.

Some health care spaces such as patient beds and operating rooms are specifically referenced in the code. NFPA 99-2012 Section 6.3.2.2.8.3 states that “patient beds, toilets and wash basins shall not be considered a wet procedure location,” while 6.3.2.2.8.4 states that “operating rooms shall be considered a wet procedure location.” NFPA 99-2012 Section 6.3.2.2.8.4 goes on to allow the health care organization the option to perform a risk assessment of the operating room to potentially define the space otherwise. NFPA 99 Annex A, A.6.3.2.2.8.4, specifies that, “In conducting a risk assessment, the health care governing body should consult with all relevant parties, including, but not limited to, clinicians, biomedical engineering staff and facility safety engineering staff. This is important to consider for any facility considering this atypical approach.”

With the safety of the patient being the goal of these code requirements, it is fair to question why an argument even exists over which space is a wet procedure location.

Understanding the design and maintenance requirements of a wet procedure location is an important element in the debate. NFPA 99-2012 Section 6.3.2.2.8.1 states that “wet procedure locations shall be provided with special protection against electrical shock,” and 6.3.2.2.8.2 defines that protection as a “power distribution system that inherently limits the possible ground fault current due to a first fault to a low-value, without interrupting the power supply.”

With further clarification provided in the National Electric Code, engineers address this requirement by installing an electrical isolation panel within the space. These panels are provided with line isolation monitors, isolation transformers and are fed from a transfer switch, which is often dedicated to the panel. It is the line isolation transformer in these panels that is used to isolate what would have been the neutral from the ground.

Advances in technology and a significant increase in the amount of electrically operated medical equipment within operating rooms and major procedure rooms increases the number of branch circuits required. This may increase number or capacity of isolation panels that are required to support a space. Recognizing that isolated power adds to the construction and maintenance cost, it is important to understand which spaces will in fact be used for wet procedures. With a detailed review of each project’s needs and intentionally defining these wet procedure locations early in the design process, the engineer and owner can plan for an appropriate design.

Intervening walls

Medical gases used in patient care areas are required to have zone valves to control the flow of these gases to certain zones or areas within a facility. The intent of the zone valves are to shut off the flow of gas to a fire site (hazardous area) without staff being directly exposed to the fire or any product of combustion created in the space and allow staff to safely evacuate patients to another area of the building.

Medical staff in health care facilities are properly trained on how to operate these valves during an emergency event. While the purpose of these zone valves is generally understood, locating them to meet code requirements can often be in conflict with the architectural design of a space. This is most commonly an issue in large, open spaces such as recovery or open-bay care units where there is limited wall space.

NFPA 99-2012 Section 5.1.4.6.1 states that “all station outlets/inlets shall be supplied through a zone valve, which shall be placed as follows: 1. The zone valve shall be placed such that a wall intervenes between the valve and outlets that it controls. 2. The zone valve shall serve only outlets located on that same story. 3. The zone valve shall not be located in a room with station outlets that it controls.”

All three requirements of the zone valve location mentioned above are for the safety of the individual who would be controlling the valves. If an intervening wall is used, it may be either opaque or not, however it must be constructed with a one-hour fire rating.

The challenge that engineers often face in a largely open patient care area is that there are few walls that will accommodate the zone valves. Adjacent spaces outside these patient care areas may not be suitable for the installation of a zone valve. An example of this would be a patient waiting area. In this situation, an intervening wall in the patient area would be required.

A common strategy used by designers to design the required intervening walls while still maintaining the functional layout of a larger space is to construct a partial wall or “wing wall.” These wing walls can be constructed with glass that allows the line-of-sight to be maintained across a large space. This seems like an effective solution, however there are a few items to consider when using this design.

First, it is important to consider how the medical gas piping can be installed with the window and the height of the zone valve must also be properly coordinated. The height of the valves is dictated by NFPA 99 where it is mentioned that the zone valves “Must be readily operable from a standing position.” This creates a challenge during construction to properly install the medical gas piping while maintaining the height of the zone valves and a glass opening in the wall.

Second, when locating these zone valves, the intervening wall must be fire rated to protect the operator of the valves. In a wing wall with a glass element, the glass must be fire rated and installed with a UL listed installation. This can be much more costly to the owner of the facility and there are limited products available when compared to a nonfire rated material.

Ultimately, the installation of zone valves in an intervening wall is crucial for the protection of the patient and medical staff. Although it can be challenging, when carefully planned by the design team and owner, a space can function properly and meet the intent of the code.

The design of health care facilities offers many challenges for the design team and owner of the facility. Adherence to codes and standards such as NFPA 99 will help to ensure the design is safe for all occupants. Some code requirements may be difficult to apply, but with a proper understanding and heightened communication between the design team and owner, Successful design can be achieved.

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