Has anyone ever installed a wet pendent ultra high temperature head (ie ~500 degree head) inside an insulated roaster or some other type of application which operates at about 400 degrees?

The piping itself is only in minimal thermal contact with the 400 degree operating temperature.  Almost the entirety of the pipe system is exposed above the roaster at typical room temperatures.

Does anyone see any problem with this type of installation?  Do we have to worry about the water in the pipe boiling?

Please let me know of any questions.

Thanks in advance.

What's being roasted in the roaster and why is sprinkler protection (or another form of active fire protection) desired? Is this is a commercial cooking operation?  

They are roasting different types of nuts. The nuts sit on a conveyor belt and pass through the unit at about 400 degrees.  

I remember doing something like this a couple years ago.  The engineer involved required a dry system because he was concerned about the water boiling in the pipes.  The EOR also would not permit grooved fittings above this area either.  Thankfully, it was not a large area and the piping was relatively small.

Travis Mack
MFP Design, LLC
www.mfpdesign.com
 

Is someone requiring it???

Or you just want to to it??

How long is the conyor/. Oven????


Does not sound like it is required!!!!

The insurance carrier maybe requiring the protection. Yes dry pipe is the way to go when the temperature is above the boiling point. They may be using hot oil to heat the oven, which could above the flash point of the oil hence the protection.

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Fire Sprinklers Save Firefighters' Lives Too!


 

cdafd:
The conveyor/oven is approx. 20' long and 8' wide.


Regarding the potential for the water to boil, would the water as it warmed not circulate and rise in the pipe and draw down cooler water from above, creating a warm-cool cycle?  As the warm water rises the heat will dissipate via convection and mixing and conduction via the cooler steel pipe.  

Remember that only the length of pipe needed to install a pendent head into the top of the unit is directly exposed to the 400 degree temperatures.  The rest of a large network of pipes is at room temperature.



 

At those temperatures wouldn't you have concerns about the water turning to steam?  I would be concerned about the pipe blowing out then since it would be over pressurized.

Would it be possible to use a dry pendant?

I have done several of these in Yonkers, NY for a national company called american sugar refinery.
Three issues where discuss intensely.
1) Type of system
(we chose a dry system like others in the posting to avoid freezing and boiling temperatures)
2) exposed or concealed heads to avoid debris in the fusible link. (we chose concealed since the use of plastic bags will not be feasible and also to avoid accidental discharge cause by flying debris)
3) type of piping
(we chose galvanized since all piping is exposed to outside natural elements)


   

Unfortunately the highest dry pendent is 286.

With the pipe filled with water at 100 psi, would steam be present?

I'm thinking about going with a 2" deluge valve to open heads and installing heat detectors in the roaster.
 

So who is requiring the protection??  

I would agree with a deluge system that's activated by heat detection. If you can make it work I would seriously consider linear heat detection cable. It requires less maintenance and is extremely reliable. I'm unsure if Protect-o-Wire is listed for the indicated temperature.

FYI, nothing in the International Mechanical Code or International Fire Code would require active fire protection for this. Since the nuts are dry roasted, the process would not produce grease-laden vapors, which is the dominant criteria for an automatic fire-extinguishing system.

The dryers I have seen use steam for fire suppression..  Will your sprinklers be able to get full coverage?   If there is steam is available i'd go with that...  But that is the owner or their insurance companies decision of course.   Just thought I would mention.   Deluge sounds feasible, and with a conveyor belt makes the most sense...   Since you'd be trying to hit a moving target..
 

Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.