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September 23, 2001

                   Northwest NICET Newsletter 
================================================================
Volume 1 Issue 13                                      9-23-2001
================================================================

        News for Fire Protection Engineering Technicians
        ------------------------------------------------

Contents:
---------
- News
- Tech Stuff
- Test Dates
- Class Schedule
- Administrivia

================================================================
NEWS
================================================================

Next Saturday, September 29, is the mail deadline date for those of you
planning to take a NICET examination on November 17. Call or email me if
you have questions regarding your application.

================================================================
TECH STUFF
================================================================

Detector Spacing
----------------

This is project # 2 for those of you attending the seminars at Clackamas
Community College recently. Read through the example then perform the
problem that follows, send it to me by 10/7/01. Feel free to send me the
answer even if you didn't attend the seminar. If you have questions,
email me at TheBakerGroup@home.com or call me 8am-5pm Mon-Fri at
503-630-2896.


Layout a system of heat detectors in this example of a warehouse, to be
used for sprinkler system pre-action.


|<--------------- 300' ---------------->|
+---+---+---+---+---+---+---+---+---+---+ -
|   |   |   |   |   |   |   |   |   |   | ^
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | 256'
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | v
+---+---+---+---+---+---+---+---+---+---+ -

  ^   ^   ^   ^   ^   ^   ^   ^   ^   ^
  |   |   |   |   |   |   |   |   |   | 
24" deep beams forming (10) 30' wide bays


Level ceiling height = 20 feet
Ceiling surface = 24" deep beams
Manufacturer's heat detector listed spacing = 50'
Maximum ceiling temperature = 110 degrees F


Step 1)
-------
When designing a fire detection system, consideration should be given to
ceiling height, ceiling surface, slope of ceiling, and system purpose.

In this example, relevant code does not require a heat detection system,
however, the property owner wants to use a heat detection system as
sprinkler system pre-action.


Step 2)
-------
The manufacturer's listed spacing (S) for each detector is 50'.

This spacing may be required to be modified by ceiling height, surface,
and slope:

S = 50'


Step 3)
-------
NFPA 72-1999 Table 2-2.4.5.1 requires that we modify spacing of heat
detectors to 40% of listed spacing:

S = 50' X .64 = 32'


Step 4)
-------
NFPA 72-1999 2-2.4.3 requires, among other things, that for ceilings
with beams that project more than 18" below the ceiling and that are
more than 8' on center, each bay formed by the beams will be treated as
a separate area.

The example illustrates (crudely) 24" deep beams spaced 30' on center,
therefore each of the bays formed by the beams will be treated as a
separate area.


Step 5)
-------
NFPA 72-1999 2-2.4.1.1 is the 'either-or' article;

either install detectors within a distance of one-half listed (and
modified) spacing measured at right angles from all walls or;

all points on the ceiling will have a detector within a distance of .7
times listed (and modified) spacing.


Step 6)
-------
NFPA 72-1999 2-2.3 The temperature rating of the heat detector will be
at least 20 degrees F above the maximum expected ceiling temperature.

The example data will require at least a 130 degree F heat detector.


Step 7)
-------
Layout the detectors using the modified spacing of 32'.

NOTES
-----
Rx = Row number 1 - 9
Cx = Column number 1 - 10 
(For example: R1C1 = The heat detector located at the point
corresponding with the point of intersection between Row 1 (R1) and
Column 1 (C1))

     |<--------------- 300' ---------------->|
     +---+---+---+---+---+---+---+---+---+---+ -
R1-> | H |   |   |   |   |   |   |   |   |   | ^
R2-> | H |   |   |   |   |   |   |   |   |   | |
R3-> | H |   |   |   |   |   |   |   |   |   | |
R4-> | H |   |   |   |   |   |   |   |   |   | |
R5-> | H |   |   |   |   |   |   |   |   |   | 256'
R6-> | H |   |   |   |   |   |   |   |   |   | |
R7-> | H |   |   |   |   |   |   |   |   |   | |
R8-> | H |   |   |   |   |   |   |   |   |   | |
R9-> | H | H | H | H | H | H | H | H | H | H | v
     +---+---+---+---+---+---+---+---+---+---+ -
      C1  C2  C3  C4  C5  C6  C7  C8  C9  C10

Because this is a regularly shaped rectangle, we can find the total
number of heat detectors required by first determining the perimeter
spacing then multiplying the number of detectors in C1 by the number of
detectors in R9.

The number of detectors in C1:
Using one-half listed spacing from the perimeter walls;

.5 X 32' = 16'
256' - 16'(R1C1) = 240'
240' - 16'(R9C1) = 224'
224' / 32' = 7

7 detectors plus the two outside detectors (R1C1 & R9C1) = 9

Each column, C1 through C10, will require 9 detectors to meet the
requirement that we treat the bays formed by the beams as separate
areas. 

10 bays X 9 detectors per bay = 90 detectors

----------------------------------------------------------------

Try this one on your own:

Layout a system of heat detectors in this example of a warehouse, to be
used for sprinkler system pre-action.


|<--------------- 300' ---------------->|
+---+---+---+---+---+---+---+---+---+---+ -
|   |   |   |   |   |   |   |   |   |   | ^
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | 100'
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | |
|   |   |   |   |   |   |   |   |   |   | v
+---+---+---+---+---+---+---+---+---+---+ -

  ^   ^   ^   ^   ^   ^   ^   ^   ^   ^
  |   |   |   |   |   |   |   |   |   | 
24" deep beams forming (10) 30' wide bays


Level ceiling height = 28 feet
Ceiling surface = 24" deep beams
Manufacturer's heat detector listed spacing = 50'
Maximum ceiling temperature = 115 degrees F


extra credit:
-------------
How do we modify heat detector spacing for ceiling heights that exceed
30'?


================================================================
TEST DATES 
================================================================

Oregon
------
PCC Sylvania, Portland;
Test 11/19/01. Postmark deadline 9/29/01.

Clackamas Community College, Oregon City;
Test 11/19/01. Postmark deadline 9/29/01.

Washington
----------
Bates Technical College, Tacoma;
Test 11/19/01. Postmark deadline 9/29/01.

Walla Walla Community College;
Test 12/14/01. Postmark deadline 10/27/01.

Spokane Community College;
Test 10/20/01. Postmark deadline 9/1/01.

Idaho
-----
Boise State University;
Test 11/17/01. Postmark deadline 9/29/01.

Ricks College, Rexburg;
Test 12/15/01. Postmark deadline 10/27/01.

Montana
-------
Rocky Mountain College, Billings;
Test 10/20/01. Postmark deadline 9/1/01.

Montana Tech, University of Montana, Butte;
Test 11/16/01. Postmark deadline 9/29/01.

MT State University, Bozeman;
Test 12/15/01. Postmark deadline 10/27/01.

Flathead Valley Community College, Kalispell;
Test 11/17/01. Postmark deadline 9/29/01.

For a complete list of all test centers and test dates, point your http
client to --> http://www.nicet.org/tests.shtml

================================================================
CLASS SCHEDULE 
================================================================

Clackamas Community College is sponsoring a 16-hour Saturday Seminar(r)
in October:

--> 10-20-2001 8am - 5pm NICET Certification application process and
Fire Alarm Systems Level I Element Review

--> 10-27-2001 8am - 5pm Fire Alarm Systems Level II Element Review

Visit http://www.lerc.org for more information and to register.

================================================================
ADMINISTRIVIA 
================================================================

For those of you interested in having a web site created, hosted,
maintained, etc., I highly recommend Doug Hockinson at
http://www.metrodenver.org. He does a great job of taking care of the
'bits behind the scene' so you end up with a site that works the way you
expect it to for a reasonable price.

Send your contributions, suggestions, comments, and questions to -->
mailto:TheBakerGroup@home.com

To unsubscribe, click the reply button and type 'unsubscribe' in the
subject line.

Good luck and have fun!

Mike  http://go.to/baker

================================================================
NW NICET Newsletter Copyright (c) 2001 Michael B. Baker
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