NEMA 3R In Elevator Equip. Rm.

[ed downey]

I Have A (2) Story Medical Office Building With (3) Elevators. The City Inspector Is Requiring That I Install The Elevator Shunt Trip Disconnect Switch In A NEMA 3R Enclosure Or Move The Shunt Trip Portion Of The Disconnect To The Circuit Breaker In The Main Switchboard Feeding The Elevator. I Have Looked Through 620.51 And I Cannot Find Anything That Would Require This And I Have Never Had To Do This Before. Any Insights Or References To Other Codes Would Be Helpful In Making Me Understand His Reasoning Before I Make The Call To Him On Monday.

On A Side Note He Is Also Requesting That All Conduit In The Elevator Pit Be PVC.

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

Hi Ed,

Does the building have a sprinkler system?

Dave

 

[jerryb]

Re: NEMA 3R In Elevator Equip. Rm.

I've never heard of requiring Nema 3R enclosures or using PVC in the pit. Article 610 really does not deal with elevator installations. What you need to look at is ASME A17.1 "Safety Code for Elevators and Escalators".

I know that Bussmann makes their elevator Power Module switch which is both fused and comes with shunt-trip contactor. Their literature says that the enclosure comes as Name 1 and UL 50 Listed.

 

[ed downey]

Re: NEMA 3R In Elevator Equip. Rm.

Websparky, Yes The Building Is Sprinklered.

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

Ed,

Here is a possibility;

Some states elevator codes require 3R enclosures when a sprinkler system is installed in an elevator equipment room IF the shunt trip device is located in the room.

Logic;

If sprinkler goes off in eq. room and soaks electrical controls while energized, big problem!

Here in Ohio, on the elevator eq. rooms that I have worked on, the shunt trip device was located at the main panel room. Hence, the power will be shut off to eq. room when the heat detector located in the top of the shaft or the eq. room is triggered. The heat detectors are designed to trigger before the sprinkler heads melt, thus killing all power to the evevator eq.

Maybe this is what the inspector is going with??

Hope this helps!

Dave

 

[ed downey]

Re: NEMA 3R In Elevator Equip. Rm.

Websparky,

Do You Know What Section Of The Elevator Code He Might Be Referring To So That I May Review It Prior To Talking To Him On Monday.

If This Is A Requirement I Would LIke To Catch It During The Design Phase Of The Project From Now On.

 

[brian john]

Re: NEMA 3R In Elevator Equip. Rm.

Requiring NEMA 3R equipment because the building is sprinklered shows a total lack of what happens during a fire. When the sprinklers go off and the water hits the flames an amazing thing happens, the liquid turns into steam, and short of utilizing explosion proof enclosures, nothing you do will stop the steam. I have seen these countless times in electrical rooms that are sprinklered. Of course logic doesn’t have a lot to do with the thinking on some.

In Washington DC (DC has their own codes) the fire marshal requires sprinklers in electric rooms (this may be a national requirement). The electric inspectors require NEMA 3R gear or shielding of the sprinklers or switchgear with sheet metal, but only in the main electric room.

 

[ed downey]

Re: NEMA 3R In Elevator Equip. Rm.

Brian,

I am With You On This One It Does Not Make Any Sense To Require NEMA 3R Devices Just Because It Is Sprinklered. 1.) If The Sprinkler Goes Off You Have Bigger Problems Than Worrying If The Elevator Continues To Run, & 2.) If Your Going To Require It In Elevator Equipment Rooms Why NOt In The Rest Of The Building Also (It Has Electrical Devices That Will Be Subject To Getting Wet When The Sprinkler Goes Off). Things That Make You Go Hmmmm!

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

Hi Ed,

Each state has different elevator codes.
I will look-up Ohio's code and get back to you.

Remember, I was only guessing!

Thanks,
Dave

 

[pierre]

Re: NEMA 3R In Elevator Equip. Rm.

Ed

When an inspector cites a job, is he not required to give a location of whatever code he is using for reference. I know some Inspectors think this is like engineering a job (and in some cases I sympathise with them), but how else is this done

Pierre

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

Ed,

ASME codes hold the answer. I am trying to get a copy.
I did find ASME code for the shaft requiring NEMA4 equipment when sprinkled.

Stay tuned........

Dave

 

[iwire]

Re: NEMA 3R In Elevator Equip. Rm.

Originally posted by websparky:
I did find ASME code for the shaft requiring NEMA4 equipment when sprinkled.

After reading this I am wondering if these requirements have to do more with protecting the equipment from damage if the sprinkler system leaked or a head broke when there is no fire.

If I was riding in an elevator I would want all the limit switches and control circuits in the shaft to stay dry.

One question though, if we must install a 3R disconnect do the elevator guys install a 3R control cabinet?

 

[bwyllie]

Re: NEMA 3R In Elevator Equip. Rm.

MA has done away with the shunt tripping requirement all together.

 

[roger]

Re: NEMA 3R In Elevator Equip. Rm.

bwyllie,

MA has done away with the shunt tripping requirement all together.

this type of solution could possibly be considered "good" or "common" sense, therefor being in violation of any code.

Roger

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

bwyllie,

Really?!

Shunt trip breakers are a necessity for elevators according to ASME standards for life safety. The shunt trip used in conjunction with a fire alarm system is what keeps firefighters as well as passengers alive during a fire in an elevator shaft or equipment room.

Please supply a reference to your state's code you are quoting.

Thanks,
Dave

 

[iwire]

Re: NEMA 3R In Elevator Equip. Rm.

To me as I have seen someone say before a shunt trip breaker on a elevator makes a coffin hanging on a rope.

To me elevator recall through smoke detectors on the landings is the way to go, not shutting it down.

Some of the hydro units will come back to the main floor on loss of power but cable units stop wherever they are.

Why would you want that?

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

iwire,
First, smoke detectors do not operate shunt trips.

Here is the way elevators operate during an event;

At the top of the shaft there is a separate smoke detector, a separate heat detector and usually a sprinkler head. Same for the equipment room.

The system is designed to have the smoke detector trip first when smoke is detected. When this happens, a signal is sent to the elevator equipment to send the car to the recall floor which is usually the first floor of the building. During this process, the "red fireman's hat" symbol and a tone is activated in the car which warns the occupants to exit the elevator. The next event, if there is a fire in the shaft or eq. room, the heat detector will trip and cause the shunt trip device to kill all power to the equipment. The third event, is the sprinkler head melts to extinguish the fire.

Is it fool proof? NO. Persons that want to defeat a safety system are always fools. Does it work? YES. The idea of the shunt trip is to minimize the possibility of a firefighter or other person to use the elevator in this situation. Once the elevator goes to "recall", the only person that can operate the car is a fireman with the key to the car to put it in manual override.

I hope this helps!

Dave

[ July 04, 2003, 12:07 PM: Message edited by: websparky ]

 

[iwire]

Re: NEMA 3R In Elevator Equip. Rm.

Dave I install the fire alarm system side of recall systems and understand about them, I am still at a loss as to why we need a shunt trip.

As you say once recall is activated only fire personal can operate the elevator.

If a fireman is in the car operating it with his key for whatever reason (heroic rescue or just a bad choice) why would we want to kill the power?

The only way I see the shunt as a good idea is if it is tied into the elevator controller in a way that the shunt can only operate once the car is parked with doors open on the primary or alternate recall floor.

It scares the heck out of me that we could cook a firefighter that has chosen to use his key.

The idea of the shunt trip is to minimize the possibility of a firefighter or other person to use the elevator in this situation.

That is a fine goal, but to have the elevator power cut off regardless of the position of the car and doors seems like a poor way to go about it.

JMO Bob

 

[websparky]

Re: NEMA 3R In Elevator Equip. Rm.

Hi Bob,

I agree with you.

In most states the ASME Standards have been adopted since 1996 for elevators. According to their research and tracking of events, the standard have been proven to be effective when it comes to life safety.

Typically, a smoke detector will trip long before a heat detector will trip. This time delay allows for the car to return to the recall floor safely.

The other intent of the shunt trip is to be sure only qualified personnel, not the firefighter, not the maintenance guy, but the licenced fire alarm person can reset the fire alarm system and reset the shunt trip. The shunt trip will not reset unless the fire alarm is reset first. This helps insure that the life safety event is over and the elevator is put back into service only after all is safe.

It is not perfect, but it does work. Not to mention, no one has come up with a better plan yet!

Thanks,
Dave

 

[hornetd]

Re: NEMA 3R In Elevator Equip. Rm.

I have a better plan. Require that the portion of the sprinkler system that covers the elevator shaft and machine room be the preaction type. Preaction sprinkler piping does not contain water until the fire alarm or other control system has operated the preaction valve to admit water to the piping.

The sequence of operation would be
ignition
smoke detection (first preaction switch closes)
recall
initiation of firefighter service
heat detection
override firefighter service to recall landing
Shunt trip
elevator power monitor relay (second preaction switch) relaxes thus tripping preaction valve
sprinkler head fuses
Water flows onto fire and onto deenergized elevator equipment.

Notice that unless elevator power and fire alarm system both operate the preaction valve does not open and water will not flow onto elevator controls.

Let me just say that I have considerable self interest as a volunteer firefighter in not having the shunt trip operate while I'm in the car between floors. My self contained breathing apparatus is only good for forty five minutes of air. I somewhat selfishly believe that if I'm willing to crawl down long snotty hallways looking for other peoples relatives that I should be worth the additional cost of the preaction valve(s) and controls.
--
Tom