Performance Based Design: Fire Alarm Visual Notification Appliances - Mathematical Guide Ernesto Vega Jánica, EE, MSc, MEng 1
Performance Based Design Introduction Change on Philosophy 1999-2002-2007-2010-2013 Prescriptive Codes Vs Performance Based Design 2
Strobe Calculations Pros & Cons $ Financial Company R&D TM Project Owner Marketing Technical End-User 3
Engineer Design Brief What is Our Goal? Room Configurations & Applicable Rules 25% Performance Criteria NFPA 72 Vs UL 1971 Critical Design Assumptions 20% Design Features Method of Evaluation Mathematical Guide & Modeling Reference Model Examples 15% 15% 15% 10% 4
Performance Based Design What is Our Goal? The Strobe Calculator intends to Satisfy provisions of the NFPA 72 and the UL 1971 for building room configurations not listed on the NFPA 72, 2010* Tables 18.5.4.3.1(a) and 18.5.4.3.1(b) *NFPA recently released the NFPA 72, 2013 Edition, but the 2010 edition still referenced in the latest editions of model building codes such as the IBC 5
Performance Based Design Room Configurations NFPA 72, 2010 Tables 18.5.4.3.1(a) and (b) as Prescriptive Code Points to UL 1971 as the PBD guideline Rule of Thumb: Designs shall provide a minimum of 0.0375 lumens/ft 2 (0.4036 lumens/m 2 ) of illumination at any point 6
Performance Based Design Applicable Rules The American with Disabilities Act, ADA The National Fire Alarm Code NFPA 72 The American National Standards Institute, ANSI A117.1 UL Standard 1971, Signaling Devices for the Hearing Impaired 7
Prescriptive Code Strobe Coverage for Irregular Areas 10 a1=30 x30 900ft 2 15cd A=680 ft 2 40 30cd Strobe 22 a2=20 x20 400ft 2 a1=30 x30 900ft 2 30cd 8
Performance Based Design Performance Criteria Minimum requirements are listed by ADAAG, NFPA 72 & UL 1971: 0.0375 lumens/ft 2 (0.4036 lumens/m 2 ) of illumination at any point and, Vertical, Horizontal and Polar Output as per UL 1971 9
Angular Derating Factor Performance Criteria 0 α 90 Angle Vertical α (Deg) Output (%) 0 100 5-30 90 35 65 40 46 45 34 50 27 55 22 60 18 65 16 70 15 75 13 80 12 85 12 90 12 UL 1971 Minimum Vertical Output, Wall Mounted 10
Angular Derating Factor Performance Criteria 90 90 α 0 Angle Horizontal α (Deg) Output (%) 0 100 5-25 90 30-45 75 50 55 55 45 60 40 65 35 70 35 75 30 80 30 85 25 90 25 UL 1971 Minimum Horizontal Output, Wall Mounted 11
Angular Derating Factor Performance Criteria 90 90 α 0 Angle α (Deg) Polar Output (%) 0 100 5-25 90 30-45 75 50 55 55 45 60 40 65 35 70 35 75 30 80 30 85 25 90 25 UL 1971 Minimum Polar Output, Ceiling Mounted 12
Performance Based Design NFPA 72 (Prescriptive) Vs UL 1971 (PBD: Strobe Calculations) MINIMUM REQUIRED LIGHT OUTPUT [cd] Maximum Room Size Wall Mount as per NFPA (cd) Wall Mount as per UL (cd) Maximum Ceiling Height Ceiling Mount as per NFPA (cd) Ceiling Mount as per UL (cd) 20 x20 15 30 10,20,30 15, 30, 55 15, 30, 75 30 x30 34 75 10,20,30 30, 45, 75 75, 75, 75 40 x40 60 110 10,20,30 60, 75, 95 75, 75, 75 50 x50 94 177 10,20,30 95, 95, 95 110, 110, 110 60 x60 135 OVER 177 10,20,30 150, 150, 150 177, 177, 177 13
Performance Based Design NFPA 72 Add Value! Wall Mounted Strobes Vs UL 1971 New Scenarios no listed in NFPA 72 MINIMUM REQUIRED LIGHT OUTPUT [cd] Maximum Wall Mount as Wall Mount as Room Size per NFPA (cd) per UL (cd) 10 x10 NA (15) 30 15 x15 NA (15) 30 18 x10 NA (15) 30 20 x20 15 30 25 x30 NA (34) 75 30 x30 34 75 38 x35 NA (60) 75 40 x40 60 110 44 x44 NA (75) 177 48 x50 NA (94) 177 50 x50 94 177 14
Performance Based Design NFPA 72 Vs UL 1971 New Scenarios! New Savings! Ceiling Mounted Strobes Maximum Room Size MINIMUM REQUIRED LIGHT OUTPUT [cd] Maximum Ceiling Height Ceiling Mount as per NFPA (cd) Add Value! Ceiling Mount as per UL (cd) 10 x10 10,12,15 15, 30, 30 15, 15, 15 10 x15 10,12,25 15, 30, 55 15, 15, 30 20 x20 10,20,30 15, 30, 55 15, 30, 75 20 x20 12,18,24 15, 30, 55 15, 30, 30 25 x25 12,18,24 45, 45, 75 30, 30, 75 30 x30 10,20,30 30, 45, 75 75, 75, 75 40 x40 10,20,30 60, 75, 95 75, 75, 75 44 x44 12,24,30 75, 95, 95 75, 75, 75 50 x50 10,20,30 95, 95, 95 110, 110, 110 60 x60 10,20,30 150, 150, 150 177, 177, 177 15
Performance Based Design Critical Design Assumptions Inverse Square Law Vertical, Horizontal & Polar distribution as per UL 1971 Distance from Strobe to most remote point Add Value! 16
Inverse Square law Keep it Simple! P = I / D 2 P2 P = Illuminance (lumens/ft 2 ) P1 I = Effective Intensity (candela) Strobe (Source) D1 D2 D = Distance (ft) 17
Prescriptive Code Design Features 6 In rooms with Low Ceilings Middle of Lens Sect. 18.5.4.2 80-96 ADA 80-96 NFPA 72 Sync more than 2 Strobes in a field view Sect. 18.5.4.3.2.(4) Sect. 18.5.4.4.7 Sect. 18.5.4.1 NFPA 72, 2010 18
Strobe Calculations Method of Evaluation Scenarios Not Listed in prescriptive tables Wall Mounted: Horizontal & Vertical Outputs Ceiling Mounted: Polar Outputs The Strobe Calculator will recommend the next commercially available strobe Equivalent Facilitation Letter 15cd 30cd 75cd 110cd 177cd Add Value! 19
Strobe Calculations Code Compliance Facilitation Letter Department of Community Affairs -DCA- Authority Having Jurisdiction -AHJ- Explain Evaluation Procedure & Results Add Value! 20
Performance Based Design Model Interface Strobe Location: Wall Ceiling Room Dimensions: h = x = y = 12 44 44 x=wide Recommended Strobe: 75cd y=deep h=height 21
Performance Based Design Model Examples Super extra Outlet Mall 44 x44 Ceilings at 12 AFF NFPA 72 Prescriptive 80cd Strobe A=1600 SqFt 40 x40 Performance Based Design 75cd Strobe A=1936 SqFt 22
Performance Based Design Model Examples Super extra Outlet Mall ACHIEVE 14% SAVINGS $ 80,000 Over 300 Stores Sports Food Movies Home Retail $ 8,500 $ 15,000 $ 22,000 $ 21,000 $ 13,500 23
Equivalent Facilitation Letter 24
Performance Based Design Model Examples Add Value! What about existing buildings? Existing Strobes not in compliance with proper coverage? Limited Wire, Circuit Runs and Power Supplies? Landmark or Sensitive Areas or Buildings? What would be the Maximum Coverage if...? 25
Performance Based Design Where do we see more add Value? MINIMUM REQUIRED LIGHT OUTPUT [cd] Maximum Room Size Maximum Ceiling Height Ceiling Mount as per NFPA (cd) Ceiling Mount as per UL (cd) New Scenarios! New Savings! Ceiling Mounted Strobes 10 x10 10,12,15 15, 30, 30 15, 15, 15 10 x15 10,12,25 15, 30, 55 15, 15, 30 20 x20 10,20,30 15, 30, 55 15, 30, 75 20 x20 12,18,24 15, 30, 55 15, 30, 30 25 x25 12,18,24 45, 45, 75 30, 30, 75 30 x30 10,20,30 30, 45, 75 75, 75, 75 40 x40 10,20,30 60, 75, 95 75, 75, 75 44 x44 12,24,30 75, 95, 95 75, 75, 75 50 x50 10,20,30 95, 95, 95 110, 110, 110 60 x60 10,20,30 150, 150, 150 177, 177, 177 Discard non-commercially available ( ) 26
any? 27
Ernesto Vega Jánica. EE, MSc, MEng any? evega@rjagroup.com evj2@hotmail.com 28
Thank You! References ADAAG Visible Notification Sections 4.28.3 and 2,2 Equivalent Facilitation NFPA 72, National Fire Alarm Code, 1999, 2002, 2007, 2010 & 2013 Editions UL Standard for Safety 1971, Signaling Devices for the Hearing Impaired SFPE Handbook of Fire Protection Engineering, 3rd Edition SFPE Engineering Guide to Performance-Based Fire Protection, 2nd Edition Credits Dr. James Milke. University of Maryland Rolf Jensen & Associates. New York City 29