lights and sprinkler heads

[gotnoblue]

due to an add-on thrust to our main stage, i need to relocate some lights to the structural steel over the house. the ideal placement for the light (ideal for achieving 45 degree angle, cleanest and safest cable run) puts the light 30in below the sprinkler.

so . . . what is the minimum safe distance between a 575w strand and a sprinkler head? the base of the light where the lamp rests is directly below the beam, obscuring direct heat release into the sprinkler head, if that helps.

am i safe? or will i make it rain this sunday?

thanks,
ed

 

[tjrobb]

I'd have to check, but 30" should be OK. PLEASE PLEASE PLEASE talk to your fire marshal to make sure he's OK with the lights, you might be affecting spray. I am not a fire protection engineer and can only speak in generalities.

 

[derekleffew]

. . . what is the minimum safe distance between a 575w strand and a sprinkler head? ...

Interesting question.

What color is the liquid in the sprinkler head in question?

Swift Fire Protection Blog: Fire Sprinkler Head Temperature Color Codes

I can't find the pertinent documentation on the Strand (assuming SL) fixture, but here's some information from a competitor's products:
KnowledgeBase: Source Four Heat Ratings/ How Much Heat Does the Source 4 Emit? - Electronic Theatre Controls

S4/S4 Zoom/750w

• Lamp Focus Knob: 210°C (410°F) max.
• Exterior Rear Housing Skin: 217°C (423°F) max.

S4jr/S4jr Zoom/575w

• Lamp Focus Knob: 210°C (410°F) max.
• Exterior Rear Housing Skin: 235°C (455°F) max.

Interesting to note that the 575W S4jr. reaches a higher skin temp. than the 750W full-size.

Someone with training in thermo-nucular-dynamics should be able to tell you what the ambient temperature 30" above an object that is 455°F would be. My guess is, it'll be fine, but I don't think I'd risk it.

 

[JD]

The biggest variable is airflow. If air is moving, you should be ok, but if the air is not moving, heat can pool directly above the fixture and even 30 inches up can get hot.

 

[gotnoblue]

the liquid is red. thanks for the handy chart.

 

[gotnoblue]

The biggest variable is airflow. If air is moving, you should be ok, but if the air is not moving, heat can pool directly above the fixture and even 30 inches up can get hot.

the ac vents are approx. 12 feet below this hanging point, and are "focused" horizontally over the audience. there is airflow, but not directed to this position. i am thinking that i will rehang just to play it safe. thanks for the reply.

 

[Call911]

After seeing firsthand the amazing damage a burst sprinkler head can have, I'd say don't even risk it.

Working for a high school district, I see some pretty stupid things. In my last ten years I've seen sprinkler heads burst three times. Once was when a softball, that managed to fly through the rafters, miss all the basketball net hardware and curtains, and nail a sprinkler. 15 minutes later we had a second pool. The second time was when a sprinkler head near an outside door froze and broke when some genius propped the door open all day. The third time was the best of all, when the cleaning crew propped a ladders up against a sprinkler head, and the pressure was so much it popped in the middle of the night. The flow sensors aren't tied into the fire alarm, just local bells on the main lines. Didn't find that until about after 8 hours of flowing water, onto the hardwood gym floor. I've never seen wood ripple like that before, the gym floor looked like it had waves. Amazing. At least we got a new gym floor out of the deal.

Moral of the story: don't mess with sprinkler heads. Don't even look in their general direction. They are pure evil (but life saving).

 

[DuckJordan]

Notice all of that deals with pressure and not heat. That said our 2k fresnels are less than 5 inches from a red tip sprinkler head. They also run about 8 hrs a day continuos

 

[tjrobb]

Red bulbs will trip at ~155*. Higher temp equals faster time. They also are rated at a normal ambient not to exceed 100*. Related to water damage is water smell. Parts of your system may not have had flow in years. Stagnant water and pipe oil are a stinky combination.

 

[kiwitechgirl]

I hung a Selecon Pacific off a pipe which was about 4 inches below a sprinkler head. The Pacific was on for 3 hours, heatsink directly under the sprinkler, before it went off (and no, I didn't do this deliberately!). I wouldn't recommend it...30 inches though is very different. Can you do some tests with a lamp and a thermometer? It won't be exact, but will give you a rough idea of whether it's going to be close or not.

 

[TimMiller]

I think you should be safe but I would check with your fire marshal or give your fire system contractor a call. Sprinkler water is absolutely discusting and will stain anything and everything. It also doesn't have a very good smell.

 

[Esoteric]

Check with your local fire Marshall for sure, but we have hung 500W PAR64's at 24" from sprinkler heads before with approval. It really does depend.

 

[TimMiller]

Also if you have not begun to know your local fire marshal its time to. You do not want to get on their bad side or they can make your life difficult. Be on their good side and they will be more than willing to help you out.

 

[emoreth]

But what if you can't find a fire code expert named Marshall? Would a Fire Marshal work just as well?



(Sorry if I'm being an annoying smartass. That spelling mistake really bugs me )

 

[Cooperhodges]

I work for a Fire Inspector, and the photo you gave gives me concern. I would check NFPA regulations before you mount anything.

 

[TimMiller]

Lol I didn't even catch that, gotta love the auto suggestion on cell phones, I fixed it for you.

 

[Beans45601]

I am surprised no one has said this yet, but just move the light. It's not worth the worry and cabling aside, 45* is just a suggestion, nothing you have to live by and nothing anyone will notice. Move it for a 40* or 35* angle if it solves the sprinkler head issue. Don't worry about it!