Fire Pump Electrical Safety for Service Personnel
Fire pumps are an important component in fire protection systems as they provide the required water pressure that these systems need to operate. Requirements for the installation of fire pumps are covered in NFPA 20 Standard for the Installation of Stationary Pumps for Fire Protection. In order to ensure the availability of power to fire pumps, NFPA 20 discourages the installation of a disconnecting means and features that limit overcurrent protection in the power supplies to electric motor-driven fire pumps. The lack of an overcurrent protection device is something that becomes important to consider when discussing the Inspection Testing and Maintenance of these fire pumps.
In order to make sure that fire pumps remain operational, NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems outlines the minimum requirements for inspection, testing, and maintenance (ITM) of water-based fire protection systems, including fire pumps. When performing required ITM on the fire pump equipment, the lack of overcurrent protection devices discussed earlier subjects service personnel to an unusual exposure to electrical shock, arc flash, and arc blasts.
Because of these dangers, some important changes were made to the 2020 edition of NFPA 25 and all the way back through the 2011 edition via tentative interim amendment to reduce the need for a service person to open up the fire pump controller to take the measurements or perform inspections if the controller could not be placed in an electrically safe work condition.
The changes that have been made to NFPA 25 now require the safe work practices within NFPA 70E Standard for Electrical Safety in the Workplace®, or an equivalent such as Canada’s CSA Z462 Workplace Electrical Safety, to be applied in addition to legally required precautions when testing or maintaining fire pump controllers. Additionally, the tests and inspections in chapter 8 that would have required a service person to open up the energized fire pump controller to take measurements or inspect connections have been alleviated if they cannot be completed without opening an energized controller. These include, but are not limited to:
- Printed circuit board inspections
- Cable and wire inspections
- Plumbing parts inspection inside of electrical panels
- Inspection of controls and power wiring connections
- Testing accuracy of pressure gauges and sensors
- Reading current pressure for fire pumps that use electronic pressure sensors to control the fire pump operation
- Recording electric motor voltage and currents (all lines)
- Testing alarm sensors within the fire pump controller (instead they can be tested at an alternative location)
It may be possible for some of these readings to be taken on an energized controller if external means are provided. Additionally, some of these inspections can be completed if the fire pump controller can be placed in an electrically safe work condition. Per NFPA 70E, this would include de-energizing the circuit, lockout/tagout of the isolation device for the controller, and confirming that the controller is in a zero energy state. In order to de-energize the controller, an isolation switch in the fire pump controller - located in a separate compartment than the other controller components - can be used. It should be noted that fire pumps are permitted to have a disconnecting means per NFPA 20 and NFPA 70® National Electrical Code® (the NEC), but due to the cost of adding such a large disconnecting means, they are not typically provided. Without a disconnecting means, it becomes much more difficult to de-energize the fire pump controller for work.
The philosophy of NFPA 70E is to complete work on de-energized equipment, which aligns well with the requirements in NFPA 25, but if there is a need to complete work, inspect, or test an energized controller, precautions need to be made in order to protect the service person from shock, arc flash, and arc blast.
There is far too much involved in NFPA 70E to cover everything in this blog, but I can give a brief overview of the options when working on an energized fire pump controller. NFPA 70E requires that a qualified service person complete a risk assessment before performing a task to determine if a hazard exists, how likely the hazard is to cause injury, how bad the injury could be if it were to happen, and what measures should be taken to protect themselves. This last part often includes the use of personal protective equipment or PPE. To determine the proper level of PPE, the service person would need to either utilize the PPE Category Method or an Incident Energy Analysis. The PPE category method is outlined in NFPA 70E, however this method relies on the clearing time of an upstream overcurrent protective device (OCPD). Since many fire pumps are supplied directly from a service and have no upstream OCPD, the service person would need to reference the information determined from an Incident Energy Analysis. This means that an incident energy analysis will have to have been performed prior to any service personnel opening an energized cabinet to perform any testing. To aid the worker in selecting PPE based on the Incident Energy Analysis, NFPA 70E requires that the owner label the equipment with the following:
- Nominal system voltage
- Arc flash boundary
- At least one of the following:
- Available incident energy and the corresponding working distance, or the arc flash PPE category
- Minimum arc rating of clothing
- Site-specific level of PPE
Keep in mind that only service personnel that meet the definition of a qualified person in NFPA 70E can perform this task. That means that they have demonstrated the skills and knowledge related to construction and operation of the fire pump controller and they have also received the necessary safety training to be able to identify the hazards and take the appropriate steps to reduce the risk from the electrical hazards present.
Without this labeling, the service worker cannot make a determination for safe work practice on the equipment without further assessment of the incident energy associated with the installation that needs to be provided by the owner. If the worker is able to complete the Incident Energy Analysis, or the fire pump controller is provided with an overcurrent protection device and the PPE Category Method is performed, then the service person can complete the work if they are qualified, have training in 70E and the equipment they are using, and are using the proper PPE and precautions.
In conclusion, NFPA 25 alleviates some of the inspection, testing, and maintenance on a fire pump if they cannot be completed without opening an energized fire pump controller. If there is a need to complete work inside of an energized fire pump controller, the owner of the controller and service worker will need to follow NFPA 70E to determine the proper safeguards and PPE needed when completing the work. Under no circumstances should a service person engage in work on energized equipment without determining and using the proper level of PPE and obtaining the proper level of training.
If you haven’t done so already, download the new Electrical Safety in the Workplace fact sheet that came out recently.