I’m sure everyone is familiar with glass bulb fire sprinklers. So much so in fact that they may not be familiar with fusible link sprinklers. The glass bulb is considered the standard type of sprinkler operation today. But, us older folks in the sprinkler community remember a time when the fusible link sprinklers were the standard. But did you know that the glass bulb sprinkler has been around over 80 years!
The History of Automatic Sprinkler Protection
Part 4 – Frederick Grinnell
Frederick Grinnell was born in New Bedford, Massachusetts. In 1855, he graduated from Rensselaer Polytechnic Institute. Earlier in his career, he was draftsman, construction engineer, and manager for various railroad manufacturers. He designed and oversaw construction of more than 100 locomotives.
Frederick Grinnell’s career in fire protection began at the age of 33 with his purchase of the Providence Steam and Gas Pipe Company. In the early days the company started in fire protection installing perforated piping systems, one of the first to do so. Grinnell took out a large number of patents. Under him the company became the leading fire protection company in the country. Many of the installation rules can be traced back to this company.
This is a guest post by Ryan J Smith. If you want to Guest Post, check out the Guidelines here.
Fire sprinklers have been used in the protection of many business establishments. But lately these fire protection systems have also gained popularity among home builders and home buyers alike. So what leads people to install fire sprinklers in their residences even if they have already installed smoke alarms? It is because smoke alarms merely alert occupants to a spreading fire in the house, but these devices cannot suppress it. Fire sprinklers on the other hand have proven to be very effective in controlling a fire and protecting people from its associated dangers.
According to the National Fire Protection Association, there were about 396,000 residential fires during 2005 in the United States. These fires had caused 3,055 civilian fire fatalities, 13, 825 civilian fire physical injuries, and $6.9 billion in property losses.
Studies conducted by the Federal Emergency Management Agency’s United States Fire Administration show that thousands of lives could have been saved if residential fire sprinklers had been installed in those burned homes. The installation of a fire sprinkler system could have also prevented most of the fire related injuries and substantially reduced property damage.
Residential fire sprinklers are therefore very beneficial to both people’s lives and properties. The advantages of these fire protection systems are further detailed below:
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.