Electrician Talk banner
1 - 7 of 7 Posts

·
Registered
Joined
·
275 Posts
Discussion Starter · #1 ·
Were any of you involved in the struggle over whether their would or would not be Automatic Fire Sprinklers in shaft head house and the pit of elevators?

There was a ~8 year long war between the elevator inspectors and the fire marshals who were responsible for the enforcement of the Safety Code of Elevators and Escalators (ASME A17.2.3) and National Fire Protection Association's Standard for the Installation of Sprinkler Systems (NFPA 13) respectively. The elevator inspectors had tried to prevent the inclusion of a requirement for the installation of sprinkler heads in elevator shafts into the Sprinkler standard but the fire marshals wouldn't yield and the membership of the NFPA took their lead when voting to except the new addition of NFPA 13 with the new provision included. The fire service's experience with fires in elevator shaft pits in the inevitable accumulation of trash between maintenance visits was higher than many other parts of high rise occupancies and the problem was ongoing with no easy way at hand to bring the rate of such fires down. The National Fire Protection Association's (NFPA) Standard 13 Code Making Panel refused to exempt elevator shafts from sprinkler coverage. The Fire Code Council of the NFPA declined to overrule Code making panel 13 on the issue.

The elevator regulatory people got mad that the NFPA "ignored" their concerns about the possibility of erratic operation occurring when the control mechanisms were wetted by the sprinklers. When the next addition of the Safety Code of Elevators and Escalators came out it required that every elevator shaft have a heat detector on it's ceiling that would trip 30 degrees below the trip point of the automatic sprinkler heads. When it tripped it would energize a shunt trip solenoid coil in the elevator's motive power feeder breaker and all power to the elevator traction motor or hydraulic pump would be gone. That assured that the power to the elevator's motive power was cut off before the sprinklers could discharge and effect the elevator's operation. What they didn't consider was that the instantaneous nature of the shunt trip could leave a large number of people completely trapped in coffins on tubes (hydraulic elevators) or coffins on strings (traction elevators.)

When the Safety Code For Elevators And Escalators A17.1/CSA B44-(year) came up for it's next 3 year review the American Society of Mechanical Engineers (ASME), that code's authors, came under a lot of pressure to fix the entrapment issue. Elevator equipment manufacturers and the larger elevator construction contractors were threatening to break away and write a separate code which would address the entrapment issue. Insurers were threatening to discontinue the liability protection which every business must have in place to get purchasing credit and other access to operating funds. Everyone except the American Society of Mechanical Engineers (ASME) code making panel for A17.1/CSA B44-(year) seemed to recognize the tremendous liability of building elevators that have a high likelihood of entrapping users in a building on fire. The fire service saw themselves as a very likely source of victims of such entrapments and some suspected that was intended as a way to force the NFPA to yield on having fire sprinklers in the elevator shafts.

To lower the pressure from these other players, without yielding their point that installing automatic fire sprinklers in elevator shafts was dangerous, ASME's code making panel for the Safety Code For Elevators And Escalators added a requirement that an indicator light be installed in each car which would backlight the outline of a traditional firefighters helmet. That would warn that the timer had started which would energize the shunt trip. I don't remember what the timer was to be set for. This would allegedly provide people with enough time to exit the car and avoid entrapment. No instruction sign was required by the language of that addition of the Safety Code For Elevators And Escalators. Firefighters could be trained to keep a careful watch on the trip warning light and react appropriately but with no instructions the general public wouldn't have any idea what the light meant.

When that edition of Safety Code For Elevators And Escalators was published the negative reaction from all quarters got the attention of ASME's upper management. They learned that Elevator Construction Contractors were now actually getting notices of extreme hikes in liability insurance premiums. Some insurers quietly left the elevator liability market which placed more upward pressure on premiums because the remaining insurers would be bearing a concentration of a known high likelihood risk.

Then the NFPA prepared to take the fight right into the lucrative code publishing market. The NFPA began preparing language for every applicable fire code covering structures in which elevators are installed. Some of the language under consideration was a requirement that all elevator outer doors be listed fire AND smoke doors. Another provision written for the Automatic Sprinkler Code would have called for DELUGE sprinkler coverage of all affected elevator lobbies. (Deluge sprinklers do not have individual mechanism for opening the discharge orifice. When the fire detection system detects signs of fire in the protected area from, heat detectors, smoke detectors, or flame detectors a valve opens to supply enough water for all of the sprinklers in the protected area to discharge their designed flow simultaneously thus producing a deluge of water droplets over the entire protected area. Imagine that happening in the elevator lobbies on every floor of a mid or high rise building. Language was prepared for inclusion in the Life Safety Code, NFPA 101, to require each elevator installation to be built under engineering supervision. That would mean supervisory engineering technicians would be on the job every hour of every working day of elevator construction. Bit by bit ASME's control of the elevator construction process would have been whittled away.

Once the liability insurance premiums began to pass sub orbital values everyone was suddenly interested in doing cooperative code coordination. What came out of all that was automatic return to the primary or alternate building exit floor of all elevator cars initiated by the fire detection system of the building. Pre-action control of the elevator shaft head sprinklers was also included in the Sprinkler Code. (In fire protection parlance a pre-action sprinkler system is one were the fire sprinkler system in the area protected by the pre-action system have no water in the piping until the Previous Action of another system.) In elevator shafts the pre-action required is that all cars have returned to the primary or alternate exit floor and the shunt trip in their feeder breaker/s have deprived them of motive power. The controls then open the pre-action water control valve to flood the sprinkler piping with pressurized water. (The fire sprinklers installed in pre-action system protective systems, unlike those in deluge systems, DO have individual discharge closures which will open that sprinkler only after the temperature setting of the individual sprinkler has been reached.) First comes detection, then elevator return, followed by water being admitted to the sprinkler piping. Now if the super heated combustion gasses from the fire should enter the elevator shaft each individual sprinkler will open only when that sprinklers temperature has reached it's set point. Since the power went off before the water came on no adverse effect on elevator operation caused by the wetting of the controls by the water discharging from the elevator shaft sprinklers is possible. Most importantly the elevators were all returned to a usable building exit floor and their doors stopped in the open position before the power to their motive drives was deenergized. This eliminated the risk of occupant or firefighter entrapment.

Here's the kicker though. Any change in a legally enforceable code that would require changes to what has already happened would be a constitutionally prohibited ex post facto law. The United States Constitution specifically forbids making something unlawful after it occurs. That is because that was one of the favorite reactions of the English kings when someone did something that made them angry. Since the constitutions authors had that fresh in their minds at the time of the constitution's writing that was one of the things that was "cast into stone" as never lawful. As a result there is no way to make the owners of 6 years worth of elevator construction, which occurred during a building boom, correct the entrapment risk which is built into those thousands of elevators. So any time you see the fire helmet outline light on an elevator panel it is likely that elevator represents a high danger of entrapping you in a metal box during a fire. The odds are fairly even on whether the cab you are trapped in will be above or below the fire. A convection oven? What are you talking about!

Tom Horne
 

·
Registered
36th year apprentice & Floor Sweeper
Joined
·
2,043 Posts
requirement that an indicator light be installed in each car which would backlight the outline of a traditional firefighters helmet. That would warn that the timer had started which would energize the shunt trip. I don't remember what the timer was to be set for. This would allegedly provide people with enough time to exit the car and avoid entrapment. No instruction sign was required by the language of that addition of the Safety Code For Elevators And Escalators. Firefighters could be trained to keep a careful watch on the trip warning light and react appropriately but with no instructions the general public wouldn't have any idea what the light meant.
Around here there is no timer. The smoke in the shaft sends the elevator to the primary or secondary recall floor. Then the elevator is disabled and the hat flashes. The public doesn’t need to know what a flashing hat means because the elevator is disabled. A fireman can override the elevator, but does so at his own risk, especially if the hat is flashing. While there are several smoke detectors that will send the elevator to recall, only the one in the shaft turns on the flashing hat. That would be the pre-action. Next is the heat which sets off the shunt trip.

Around here sprinklers are only required in the shaft if there is hydraulic fluid, or non-fire rated traction belts. It’s cheaper to sprinkle the elevator than it is to get fire rated traction belts.
 

·
Super Moderator
Camera and Access control specialist.
Joined
·
4,323 Posts
Interesting read. Thanks for that.

Now I know what the pre action panel does, I have one to wire at the job I'm on...
 

·
Registered
Joined
·
275 Posts
Discussion Starter · #6 ·
Around here there is no timer. The smoke in the shaft sends the elevator to the primary or secondary recall floor. Then the elevator is disabled and the hat flashes. The public doesn’t need to know what a flashing hat means because the elevator is disabled. A fireman can override the elevator, but does so at his own risk, especially if the hat is flashing. While there are several smoke detectors that will send the elevator to recall, only the one in the shaft turns on the flashing hat. That would be the pre-action. Next is the heat which sets off the shunt trip.

Around here sprinklers are only required in the shaft if there is hydraulic fluid, or non-fire rated traction belts. It’s cheaper to sprinkle the elevator than it is to get fire rated traction belts.
I wasn't writing about the present requirements for the integration of elevator and automatic fire sprinkler controls. I cannot follow why they would have integrated them in the way your describe but that is not germane to what I was writing about.

I was only trying to highlight the dangers of the elevators built under permits drawn in the 7+ years the dispute was ongoing. All of the elevators built under those codes are death traps. None of them have the kind of integration that you are describing.

Elevators built during the first cycle of the Safety Code for Elevators and Escalators, applied during the period I describe, have no warning that the elevator will loose all motive power if the heat of a fire enters the elevator shaft. I do mean none. Once the set point of the heat detector at the top of the shaft is exceeded the shunt trip solenoid coil built into the circuit breaker that protects the feeder to the elevator drive motors or motor generators opens the breaker. That deprives the elevator's machinery of ALL motive power. The Elevator stops dead in more ways than one. The controls cannot make it go anywhere because the power to the drive equipment has been cut off. It does not matter were it is in the shaft or whether it is occupied or not. As I mentioned previously many single set point heat detectors are one time use. The only way to reset the breaker and restore motive power when the shunt is controlled by a single use detector would be to cut the wires which carry the shunted breaker output to the solenoid trip coil inside the breaker's case. That would require an intimate knowledge of how the circuit was designed and how it was actually built.

The following 3 year cycle the only thing that changed was that a delay prior to the loss of power and an indicator in the cab of each elevator about to be affected was added to the Elevator Code. That additional requirement does not provide any elevator control such as cab return to a primary or alternate building exit floor. It only allows people that somehow have learned about the danger to take escape actions when the warning indicator activates before trip coil is energized to open the breaker. No instructions or warning about the hazard was posted in the elevator cabs.

That makes a period of about 7 years during which elevators which are truly an immediate danger of loss of life to the users were built. Because there is no way to compel the correction of those dangers they'll be around as long as the buildings they are part of continue to stand unless someone discovers a way to make the corrective work a part of the legally required periodic maintenance and thus not a retroactive enactment which will not survive constitutional review.

Tom Horne
 
1 - 7 of 7 Posts
Top