Ten Common System Design Mistakes & How to Avoid Them. Speaker Ken Wagoner, SET

Transcription

1 Ten Common System Design Mistakes & How to Avoid Them Speaker Ken Wagoner, SET All NFPA-13 References are from the 2002 Edition. Similar wording is contained in the 1999 edition, however the paragraph numbering is not identical All emphasis is by the presenter, and not contained in the original text of NFPA-13 Presented February 28,

2 10 Common System Design Mistakes & How to Avoid Them Speaker Ken Wagoner, SET Kenneth W. Wagoner, SET, a 1977 graduate of Bethany College (KS), owns and operates Parsley Consulting Engineers, Escondido, California. He holds NICET certifications in Sprinkler System Layout, Fire Alarms, Inspection & Testing, and Special Hazards, and is an NFPA Certified Fire Plan Examiner. He is a member of AFSA, UFCA, NFPA, and the San Diego Fire Protection Assn. 2

3 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS NFPA-13, Section establishes that for sloped ceilings in NON-STORAGE applications that the system area of operation shall be increased by 30 percent without revising the density when spray sprinklers, including extended coverage sprinklers (per ), large drop, and quick response sprinklers are used on sloped ceilings with a pitch exceeding one in six (a rise of two units in a run of 12 units, a roof slope of 16.7 percent) in non-storage applications 3

4 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS NFPA-13, Sections 8.4.3, and limit the use of ESFR sprinklers to buildings or areas with roof or ceiling slopes not exceeding 2 in 12 NFPA-13, Section cautions that the criteria in chapter 12 relating to protection of storage is intended to apply only to buildings with ceiling slopes not exceeding 2 in 12 4

5 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS NFPA-13, Sections advises that the criteria in section 12.4 covering tire storage is limited to buildings or areas with roof or ceiling slopes not exceeding 2 in 12 Sprinkler listing criteria may limit or modify sprinkler operating characteristics relative to slope of roof/ceiling 5

6 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS Partial catalog data sheet from Tyco- Fire, CC2 sprinkler, showing limits of ceiling slope 6

7 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS Partial catalog data sheet from Tyco- Fire, LF-II residential sprinkler (TY2234), showing revisions to minimum flow/press ure relative to ceiling slope 7

8 Common Mistake #1 NO ROOF SLOPE INFORMATION ON PLANS Full height cross section on plans (as required by NFPA-13, (4), should include information detailing roof slope, and be verified Hydraulic calculation cover sheet should include line item to indicate roof slope was checked in determining remote area and applicability of density Catalog data sheets for automatic sprinklers should have roof or ceiling slope information highlighted 8

9 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE NFPA-13, Sections & define the types of construction, broken into two categories obstructed & unobstructed. Annex notes for establish criteria for seven examples of obstructed construction Annex notes for establish criteria for five examples of unobstructed construction 9

10 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE Table (a) establishes maximum sprinkler spacing for light hazard occupancies based in part on the designation of the type of construction, when using standard spray sprinklers. Table establishes maxim sprinkler spacing for extended coverage sprinklers in all occupancy classes based in part of the designation of the type of construction 10

11 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE Table establishes maximum sprinkler spacing for large drop sprinklers in all occupancies based in part on the designation of the type of construction Table establishes maximum sprinkler spacing for ESFR sprinklers in all occupancies based in part on the designation of the type of construction 11

12 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE Sections and establish minimum and maximum deflector positions based on the designation of type of construction, using standard upright and pendent spray sprinklers Section and establish minimum and maximum deflector positions based on the designation of type of construction, using extended coverage upright and pendent spray sprinklers 12

13 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE Sections and establish minimum and maximum deflector positions based on the designation of type of construction, using large drop sprinklers Section establishes the location of sprinklers and branch lines in obstructed construction using ESFR sprinklers 13

14 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE Do not allow construction type statement without detailed information on parameters of framing type: EXAMPLE: Roof (deck) framing consists of open wood trusses, with 2x6 top chord, 2x6 bottom chord, 2x4 web member. Framing spaced 3-0 on center, and framed into 30 deep Glu-Lam beams. Construction is classed as unobstructed (wood truss) per NFPA-13, A (unobstructed definition e). 14

15 Common Mistake #2 IDENTIFICATION OF CONSTRUCTION TYPE NFPA-13, Section (4) requires a full height cross section with structural member information if required for clarity. Careful review of construction type should be made prior to design prior to release of plans for review prior to stocklisting prior to installation. 15

16 Common Mistake #3 BOILER PLATE DETAILS & NOTES With the growth of CAD, and the ability to import text into a drawing, many general notes and details are generic in nature and do not accurately reflect the conditions of the project Errors in stocklisting, hydraulic calculations, pipe fabrication, installation and testing can result from failure to review general notes. 16

17 Common Mistake #3 Every general note should be reviewed prior to issuance of plans for accuracy and relevance to project: EXAMPLE: Roof (deck) framing consists of 2x12 solid wood members, 30 center-to-center, spanning up to 18-0, framed into 35 3/8 glu-lam beams. Construction is classed as obstructed (wood joist), per NFPA-13, A (obstructed type e). Note clearly indicates conditions, and provides information for verification of designations 17

18 Common Mistake #3 Every general note should be reviewed prior to issuance of plans for lack of clarity of information provided: EXAMPLE: Branch line piping to be ASTM A795 Schedule 40, Dyna- Thread, or Schedule 10 pipe, with threaded, welded or grooved fittings. Not possible to verify pipe or fittings used in calculations as there is no clear definition of which type of pipe is to be used for branch lines 18

19 Common Mistake #3 Every general note should be reviewed prior to issuance of plans for lack of clarity of information provided: EXAMPLE: System designed in accordance with requirements for [light] [ordinary group 1] [ordinary group 2] [rack storage] [general storage] Generic note with options was not edited to pick applicable design criteria prior to plans being issued. 19

20 Common Mistake #4 INCORRECT LOSS THROUGH METER IN NFPA-13D SYSTEMS Hydraulic calculations for single family residence fire sprinkler systems are required to take into account the friction loss for the flow through the water meter. NFPA-13D, Section 8.4.4(4) requires designer to review actual meter loss, for possible use in calculations 20

21 Common Mistake #4 INCORRECT LOSS THROUGH METER IN NFPA-13D SYSTEMS If actual loss from manufacturer is worse than those values in Table 8.4.4(g), that value must be used in the calculations. If the actual loss from the manufacturer is less it MAY be used instead of the value from the table, per NFPA-13D, 8.4.4(4) 21

22 Common Mistake #4 INCORRECT LOSS THROUGH METER IN NFPA-13D SYSTEMS Water Meter Loss Figures from NFPA-13D Table 8.4.4(g) Size ⅝" ¾" 1" 1½" 2" GPM PSI PSI PSI PSI PSI = Above Max rated flow of commonly available meters = Less than 1 psi 22

23 Common Mistake #4 INCORRECT LOSS THROUGH METER IN NFPA-13D SYSTEMS 23

24 Common Mistake #5 INCORRECT LOSS THROUGH VARIOUS TYPES OF VALVES Equivalent lengths for check valves in various sizes shown in NFPA-13, Table are not always in agreement with manufacturer s data sheets. Equivalent lengths or specific pressure losses through valves shown on manufacturer s data sheets should be used. 24

25 Common Mistake #5 INCORRECT LOSS THROUGH VARIOUS TYPES OF VALVES EXAMPLE 6 swing check valve is shown in NFPA-13 as being equivalent to 32 of schedule 40 pipe Friction loss per foot (Pe) for 6 schedule 40 pipe, with 400 gpm flowing is psi 32 x = psi 25

26 Common Mistake #5 INCORRECT LOSS THROUGH VARIOUS TYPES OF VALVES Sample loss chart for TYCO CV-1FR Riser Check Valve Loss for similar flow (400gpm) is 0.35 psi, and when safety factor of 15% is added, 0.40 psi 26

27 Common Mistake #5 INCORRECT LOSS THROUGH VARIOUS TYPES OF VALVES EXAMPLE 2½ butterfly valve is shown in NFPA-13 as being equivalent to 7 of schedule 40 pipe 2 ½ gate valve is shown in NFPA-13 as being equivalent to 1 of schedule 40 pipe Identification of butterfly valve as gate valve can reduce loss to friction through fitting by 85% 27

28 Common Mistake #6 NO ELEVATION CHANGE FROM TEST POINT TO BASE OF RISER Location of test hydrant is required by NFPA-13, item 10, to be indicated on plans, and included in that information is the elevation of the system relative to the test hydrant. 28

29 Common Mistake #6 NO ELEVATION CHANGE FROM TEST POINT TO BASE OF RISER 29

30 Common Mistake #6 NO ELEVATION CHANGE FROM TEST POINT TO BASE OF RISER 30

31 Common Mistake #7 NO EVIDENCE OF PEAKING FOR GRID NFPA-13, requires the designer to provide additional calculations on either side of the remote area in gridded systems to prove that the area calculated is indeed the most demanding remote area used. Computer programs which show the peaking shall be acceptable using a single set of calculations 31

32 Common Mistake #7 NO EVIDENCE OF PEAKING FOR GRID 32

33 Common Mistake #7 NO EVIDENCE OF PEAKING FOR GRID Flow plot diagram, as required by NFPA-13, Section (item 15), should also give some indication of peaking. Above sample shows remote area roughly centered between primary and secondary cross mains 33

34 Common Mistake #8 GENERIC HANGER DETAILS NOT TO SCALE Sketch 1 does not show actual scale relationship between framing member and lag screw 34

35 Common Mistake #8 GENERIC HANGER DETAILS NOT TO SCALE Sketch 2 shows relationship to width, height of framing member, and lag screw length. As a general rule, the fewer threads engaged in wood, the lower the capacity of the fastener. 35

36 Common Mistake #8 GENERIC HANGER DETAILS NOT TO SCALE Lag screws, sometimes called lag bolts, have a hex head, gimlet or cone point and a thin, sharp, coarse pitched thread. They are designed for insertion into wood and produce their own mating thread. Threading is usually 60% to 67% of the length 36

37 Common Mistake #9 REMOTE AREA NOT PER NFPA-13 NFPA-13, Fig provides that the minimum length of the remote area parallel to the branch lines is to be equivalent to at least 1.2 x Remote Area As spacing of sprinklers along branch lines may not be uniform, review of actual width is advisable. Procedure shown in A not always accurate if sprinkler spacing is not completely uniform along branch line 37

38 Common Mistake #9 REMOTE AREA NOT PER NFPA-13 Maximum spacing of 15 between branches, 8-0 between sprinklers = 120 square feet per sprinkler 1,500 square feet 120 = 12.5, or 13 sprinklers flowing in remote area 1.2 x 1500 = (±46-5¾) 8-0 spacing = 5.80, or 6 sprinklers 38

39 Common Mistake #9 REMOTE AREA NOT PER NFPA-13 Sprinkler spacing is not a consistent 120 square feet for each sprinkler, therefore the quantity of 13 sprinklers flowing is not enough to achieve at least 1,500 square feet of remote area. In the example, it takes 18 sprinklers to cover at least 1,500 square feet 39

40 Common Mistake #9 REMOTE AREA NOT PER NFPA-13 Sprinkler spacing along branch lines is not consistent, therefore the number of sprinklers calculation does not result in a remote area wide enough to satisfy the requirement for 1.2 x Remote Area Six sprinklers along branch lines result in a width of only

41 Common Mistake #10 LATERAL RESTRAINT MISSING NFPA-13, requires end sprinkler on a branch line to be restrained against excessive vertical and lateral movement NFPA-13, requires restraint at invervals not exceeding 30 along branch lines, if vertical or lateral movement would result in impact against building structure, equipment, or finish materials Short Rodding or use of Tolco Fig 25, AFCON Fig 310 or other similar fitting provides restraint in vertical direction ONLY. 41

42 Common Mistake #10 LATERAL RESTRAINT MISSING 42

43 Common Mistake #10 LATERAL RESTRAINT MISSING 43

44 Common Mistake #10 LATERAL RESTRAINT MISSING An example of one method to provide lateral restraint for branch lines 44

45 Common Mistake #10 LATERAL RESTRAINT MISSING An example of one method to provide lateral AND vertical restraint for branch lines 45

46 Speaker Contact Information Ken Wagoner, SET Parsley Consulting 350 West 9th Avenue, Suite 206 Escondido, CA Ph: Fax: