Monthly Archives: January 2010
The History of Automatic Sprinkler Protection
Part 2 – The First Automatic Sprinklers
Inventors first began experimenting with automatic sprinklers around 1860 when Barnabas Wood of Nashville, Tennessee patented the first basic sprinkler. It featured a fusible solder link and operated at 165°F, still a standard temperature rating to this day. And in England, a Major Stewart Harrison of the 1st Engineer London Volunteers, developed an automatic sprinkler that apparently was a good design at the time, But neither had any success.
Henry S. Parmelee of New Haven, Connecticut is considered the inventor of the first practical automatic sprinkler head and took out his first patent in 1874. It was his third sprinkler design, in 1875, that became the one first installed commercially. It consisted of a cap, held in place by solder, covering a perforated distributor. He continued to improve this design. In 1878 it was further modified with a rotating slotted distributor which was less prone to clogging by sediment. The final version of the Parmelee sprinkler was actually done by Frederick Grinnell. He changed the thread to a ½” male fitting, and hollowed the base to separate the solder joint from contact with the water in the pipes.
Frederick Grinnell, President of The Providence Steam and Gas Pipe Company, entered in to an agreement with Henry Parmelee to manufacture his sprinklers on a royalty basis. Thousands of these sprinklers would be installed over the next few years. In 1882 he patented the automatic sprinkler that bears his name. This is considered to be the first sensitive automatic sprinkler. The Glass Disk Sprinkler came in 1890. It had a ½” orifice and a fixed deflector. It was modified in 1903 and manufactured for many years. It is probably the most common old Grinnell sprinkler to be found by collectors.
This is a guest post by Michael T Skinner. If you want to Guest Post, check out the Guidelines here.
Imagine that you, your spouse and your three children live in a 2,200 square foot, 2 story, 4 bedroom house in Anytown, USA. It is 1:30am and you are awaken by the shrill of your smoke detectors activating. As you leap from you bed, you are immediately forced towards the floor since the smoke makes it unbearable to stand erect and breathe. Your pulse rate doubles as adrenaline is being feverously dumped into your bloodstream. Thoughts enter your mind faster than you are able to process them: “What the ….?” “Where are the kids?” “How can we all get out?” “Why is this happening?”. As you open the door to the hallway you can’t see anything except an orange glow towards the stairway. Panic takes over, what do you do next? Every day in America people die in fires, most time in there own home. In 2005, 3,675 civilians died along with 87 firefighters, averaging to over 10 people dying in fires each day.i Children 5 years and under face the highest risk of home fire death.ii There is a way to reduce these numbers considerably, that way is the installation of fire sprinklers in your home. Fire sprinklers have been around for more than a century in factories, warehouses, commercial properties and public building such as schools, hospitals, and hotels. They were around long before smoke detector technology was invented and are highly reliable, yet they are resisted due to numerous myths concerning them. Fire sprinklers save lives by providing the necessary protection that allows the occupants to escape a building fire as well as reduces property damage.
Which Recessed Escutcheon?
I have run into this issue many times in the last few years. What recessed escutcheons can be used with what pendent sprinklers? The short and most correct answer is: Recessed sprinklers are listed for use with a specific escutcheon. i.e., Order the recessed escutcheon form the same manufacturer as the pendent sprinkler. All the manufacturers indicate that recessed sprinklers are to be ordered as a unit, even though most ship the escutcheons separately.
The reason this is such an issue is the number of independent suppliers of fire protection products who sell recessed escutcheons. I know a lot of fire sprinkler companies keep these generic escutcheons on the shelves and use them with what ever pendent sprinkler they got the best price on that week. It eliminates an inventory headache and helps reduce costs. But what is their liability?
After a lot of checking on the web I found only one manufacturer of escutcheons which was UL listed. ARGCO is UL listed File EX4170 and their product data states :
There is no possibility of a sprinkler head failure due to ARGCO escutcheons. It is no longer a warranty issue, since UL announced, “Installed properly, the product cannot affect sprinkler head operation.”
So while the possible liability of installing pendent sprinklers with generic escutcheons might be small, It would seem prudent to at least use a manufacturer such as ARGCO which provides a UL listing and would stand behind their product.
I for one, however, will continue to specify and order escutcheons from the same manufacturer.
Do you Peak?
Fire Sprinkler Grid Systems that is. How do you hydraulically peak your automatic sprinkler system? Do you depend on the program you use for fire protection hydraulic calculations and just trust it implicitly? I have learned not to!
The basic premise of hydraulically peaking a gridded fire sprinkler system is that the hydraulically most remote area of operation will be on the most remote branch lines between the primary and secondary cross mains. The branch lines furthest away from the point where the feed main connects to the primary cross main.
The programs I used did a great job of calculation as long as you understand the assumptions and limitations. Many hydraulic calculation programs assume that the system is a box with a common sprinkler head spacing and elevation. Then they just shift the remote area by adding the distance between heads to one side and subtracting it from the other. This is perfectly acceptable if the spacing is typical, but this is not always the case. So unless the system is spaced evenly, I peak manually. I just use the automatic peaking feature to give me a starting point.
Yes, I know what your saying. It’s Hard, and the Building Department, Fire Marshall or other Authority Having Jurisdiction are approving my calculations now. Well, That’s only because they assume several things. First, that since a computer was used it’s correct. Second, that you know what you are doing. But the day when the AHJ stops making these assumptions is coming. They have been learning!
Will the remote area be between the mains or will out board heads be involved. Many programs assume the remote area will always stay between the mains. But that depends on how many outboard heads the system has.
How many outboard heads can I have? The easy answer is one half the number along the line in the remote area. My experience is that as long as you follow this rule, even if the remote area should include outboard heads, the difference is marginal. However if design considerations mean that the secondary cross main has more heads outboard, then a calculation should be done using the outboard heads.
Will the remote area be on the end grid lines. Right now everyone assumes this is the case, but there are situations where it will not be. I have seen calculations where the end line was sized larger than the rest of the grid to make it work. But then the remote area actually will shift across the lines and not parallel to them. Most programs assume peaking is parallel to the lines. Also, if the grid is not typical, but has different spacing along the lines due to steel, or changes in ceiling grid, the remote area will not necessarily be on the end branch lines.
So be careful. Computer programs are great tools, but you are still the one in the hot seat.