The new Art. 695 makes it effectively impossible to install electric fire pumps in the majority of large-sized campus and industrial occupancies.
One of the principal objectives of the Code is the prevention of fire due to electrical causes. In the case of electric fire pumps, however, the Code must not only assure that the fire pump wiring system won't cause a fire, but it also must assure that the wiring system is sufficiently reliable and will not contribute to a failure to extinguish a fire that probably started from some other source. This is a unique situation in the NEC.
To this end, the 1996 NEC has a new Art. 695 covering fire pumps. In covering the changes in the 1996 NEC (December 1995 issue), the observation was made that, as written, Sec. 695-3(a) and Sec. 695-4(a) make it impractical to install fire pumps in many occupancies because there isn't access to a source of supply recognized by the NEC, particularly where the facility was responsible for its own distribution. In those cases, the service point can easily be the better fraction of a mile away, and running a dedicated medium voltage feeder for such a load is prohibitive to the point of discouraging the installation in the first place.
Serving a fire pump directly from a service (or through a dedicated feeder from the service) has been a requirement in NFPA 20 for many years. When the NEC incorporated the electrical installation requirements this cycle, perhaps the most important decision was whether the NEC would carry over the direct service rule. CMP 15 thought it was a bad idea and modified it.
The Fire Pump (NFPA 20) Committee passionately disagreed, and the result was a pitched battle on the floor of the Annual Meeting, a battle won (and confirmed by the NFPA Standards Council) by the Fire Pump Committee. The result is that Art. 695 as printed in the NEC is not the version that the NEC Committee wanted.
We think that this issue will be one of the most important issues that the NEC will have to face over the next few years. This is because the technical issue of how to serve a fire pump is wrapped up in a larger governance issue related to how the NFPA Standards Council implements its policy of giving other NFPA Technical Committees jurisdiction over electrical requirements that are deemed to be rooted in "performance," as was done in this case.
The sentiments expressed in the December analysis of Art. 695 were challenged in a letter from R. Schneider, who is the Engineering Manager, Fire Pump Control Business Unit, of Joslyn Clark Controls, Inc. Schneider is the NEMA representative on the NFPA 20 Committee. Instead of running his letter with others, we decided to make it the focus of this month's Code Forum. His letter reads as follows; although it isn't a question per se, we will then respond:
"There should be no argument that sprinklered buildings are the best protected from fire damage. Insurance companies' records, as well as those of NFPA, will confirm this.
"There is no question in my mind that the National Electrical Code (NFPA 70) is the finest standard to safely manage electrical power and prevent fires. The NFPA Standard on Automatic Sprinklers, which became NFPA 20, has been around since 1899, dedicated to 'putting out that fire.' When the building is on fire, NFPA 20 mandated equipment must work, and power availability under adverse and emergency conditions is a 'must.' Most likely, people's lives are at stake.
"The most reliable delivery is utility service cables directly terminated in the fire pump controller. Any additional upstream equipment or conductor routing in those cables affects power availability and reliability adversely. There are many reasons, economic and for convenience, to use upstream switches and switchboards, all of which detract from reliability because they can fail and can be left open. Please study reports from the last dozen or so large loss fires in sprinklered buildings, and you too will change your mind from the traditional NFPA 70 thinking to that of NFPA 20."
The EC&M panel's response
We will respond in two parts. First, we will make the case that, indeed, a building as shown in the drawing, on page 76, cannot be served by the medium voltage distribution system shown, regardless of its relative reliability. With that established, we will look at the consequences, and how you might approach the local inspectional authority until the rule changes.
The possible fire pump sources are covered in Sec. 695-3:
695-3. Power Source to Electric Motor-Driven Fire Pumps.
[(a).sup.x] Power shall be supplied to the electric motor-driven fire pump by one or more of the following:
(1) Service. Where power is supplied by a service, it shall be located and arranged to minimize the possibility of damage by fire from within the premises and exposing hazards.
(2) On-site Generation. Where power is supplied by on-site generation, the generation facility shall be located and protected to minimize the possibility of damage by fire.
It has been argued that the second paragraph allows installations such as the one in the drawing because of the on-site generator. Note that in order to qualify as one of the principal supplies, it would need to be a "generation facility." This is more clearly described in NFPA 20 (Sec. 6-2), from which Sec. 695-3(a) is extracted, as a "private power station." It would be the normal source for the fire pump. Very few "emergency" generators are being run 24 hours a day, serving as normal power sources. Sec. 695-3(a)(2) is only intended for large industrial facilities and the like with their own power sources that operate in lieu of or in parallel with utility power.
However, the conventional standby generator shown in the drawing could qualify as a standby source under Sec. 695-4(a):
[(a).sub.x] Multiple Power Sources. Where reliable power cannot be obtained from a source described in Section 695-3(a), it shall be from two or more of either of the above in combination, or one or more of the above in combination with an on-site generator, all as approved by the authority having jurisdiction. The power sources shall be arranged so that a fire at one source will not cause an interruption at the other source.
These sources serve only to back up a qualified principal source under Sec. 695-3(a). For example, suppose a fire pump was fed directly by a service, but the utility distribution ran overhead for many miles in a rural setting. The Authority Having Jurisdiction (AHJ) would probably view the utility source as unreliable, and a generator could be used to cure the problem. This is because the generator is being used to backup a qualified source, not substitute for such a source.
Sec. 695-3 makes no provision for double-ended substations with provisions for automatic throw-over and all the other highly reliable means that have been developed by qualified electrical engineers over generations of work on the problems of assuring highly reliable power. They have been designing these systems for use in facilities with millions of dollars at risk on any outage, precisely because utility sources may be relatively unreliable. Nevertheless, NFPA 20 and now Art. 695 brand these sources, developed through sophisticated engineering, as less reliable than a utility connection, whether backed up by an on-site generator at the building or not.
This makes it virtually impossible to install an electric fire pump in the building shown in the drawing. The only feasible alternative is to install a diesel driven pump, with its own set of problems. Again, although the Code allows for a generator, it is only in addition to one of the recognized principal supplies, and does not substitute for a remote connection to a feeder.
Instead, you have to serve the pump directly, or almost directly from the source. In this case a medium-voltage feeder would need to be run directly to the second building, probably with a dedicated transformer just outside and a feeder run from there to the fire pump controller.
What you can do now
What can be done depends on the willingness (and allowability under local law) of the AHJ to entertain a variance from the NEC provisions. Many have simply chosen to describe the medium-voltage supply at the remote building to be a service for the purposes of applying the rules. We think that may be acceptable, but only if qualified.
One of the key objections of the Fire Pump Committee to making connections that aren't directly to utility sources is that remote disconnects may be left open, particularly during shutdown periods. Fire, of course, doesn't respect shutdowns. In addition to the normal requirements for all overcurrent devices ahead of the fire pump, the feeder must be able to handle locked-rotor load indefinitely; this is why it is essential to incorporate the supervision provisions in Sec. 695-3(c) Ex. 1e. wherever there is a remote connection:
e. The disconnecting means shall be supervised in the closed position by one of the following methods:
1. Central station, proprietary, or remote station signal device.
2. Local signaling service that will cause the sounding of an audible signal at a constantly attended point.
3. Locking the disconnecting means closed.
4. Sealing of the disconnecting means and approved weekly recorded inspections where the disconnecting means is located within fenced enclosures or in buildings under the control of the owner.
Depending on local conditions, and the track record of the facility involved, the AHJ might well decide that not all of these options would be permitted in a particular case. We acknowledge the Fire Pump Committee's adverse experience with unsupervised open disconnects, and we agree that those concerns must be addressed.
We agree a properly functioning sprinkler system is the best defense against fire. We categorically reject the notion that allowing a remote connection as in the drawing is based on either convenience or economics. It is based on sound electrical engineering. It will result in increased utilization of fire pumps, with electric sources of equal or greater reliability to those now recognized in the NEC.