CANADIAN FIRE ALARM ASSOCIATION An Update on Standards, Technologies and Solutions. Smoke Characterization Study

Transcription

1 CANADIAN FIRE ALARM ASSOCIATION An Update on Standards, Technologies and Solutions Smoke Characterization Study October 29, 2008 Paul E. Patty, P.E. Senior Research Engineer Northbrook, IL Copyright Underwriters Laboratories Inc. All rights reserved. No portion of this material may be reprinted in any form without the express written permission of Underwriters Laboratories Inc. or as otherwise provided in writing.

2 Overview What is Smoke Quality Of Smoke How Do Detectors Work Ionization Photoelectric Dual Technology Smoke Characterization Project Material characteristics Smoke movement Photo/Ion response Development of Flaming & Smoldering Polyurethane Tests Flaming Smoldering p/2

3 What is Smoke Quality of smoke Color black, grey, yellow, white Particle size microns Velocity > 32ft/min. Temperature <150 degrees F Build-up rate obscuration %/ft/min. Gases of combustion p/3

4 How Do Detectors Work Ionization Chamber Technology.01 1 Microns Ionization alarms respond to the near invisible particles of combustion. When a sufficient number of properly sized particles enter the chamber the output of the chamber shifts enough to cause the alarm to activate. p/4

5 How Do Detectors Work Photoelectric Chamber Technology.1 10 Microns Light Scattering Photoelectric light scattering alarms respond to the visible particles of combustion. When a sufficient number of properly sized particles enter the chamber the output of the chamber shifts enough to cause the alarm to activate. Light scatting technology is also impacted by the color of the smoke that can reduce the output signal of the alarm as the color of the smoke darkens. p/5

6 How Do Detectors Work Dual Technology (Multicriteria) Operation Microns 1. Heat 2. Gas 3. Independent Operation 4. Signal Integration Dual Technology/Multicriteria alarms monitor for several products of combustion, and make the decision to activate based on these inputs. These types of alarms either monitor these inputs separately, or combine the signals in an effort to make a better decision of differentiating between a real fire signature, and a nuisance signature that can not be differentiated when only using an individual technology. p/6

7 Typical Response to Test Fires Alarm Technology Flaming Fire Response Time (seconds) Smoldering Fire Alarm Sensitivity Response Obscuration a (%/ft) Beam MIC Wood Paper Heptane Wood (%/ft) (pa) Ionization (58.5 min.) Photoelectric (50.5 min.) Photo/Ion (52 min.) Production Ionization (56.3 min.) 1.6 Production Photoelectric (55.06 min.) 2.5 b a. Measured in ANSI/UL 217/268, CAN/ULC- S529/S531smoke box. b. Measuring Ionization Chamber measurement in ANSI/UL 217/268, CAN/ULC-S529/S531 smoke box. Ionization alarms respond quicker to flaming fires, while photoelectric alarms respond quicker to nonflaming fires. p/7

8 Living Room Fire p/8

9 UL-FPRF Smoke Characterization Study Launched to fill gaps in previous technical studies and to answer questions raised in actual fire events - essentially a back to basics investigation. Reduced evacuation times, and questions regarding the quality of smoke. Focused on 26 common materials (and combinations) found in the home, in non-flaming (smoldering) and flaming fires. UL purchased state of the art particle size equipment and developed new protocols for measuring smoke. Study took 1 year to design, 2 years to complete and cost $700,000. The entire report (with graphs and plots) is more than 3,000 pages. p/9

10 Objective and Scope 1. Develop smoke characterization analytical test protocol using flaming and non-flaming modes of combustion on selected residential materials. 2. Fingerprint smoke by developing smoke particle size distribution data, chemical signatures and smoke profiles for materials found in residential settings for both flaming and non-flaming modes of combustion. p/10

11 Objective and Scope 3. Provide data and analysis to the industry for several possible initiatives: A) Develop recommendations to the current residential smoke alarm standards CAN/ULC-S531 (ANSI/UL 217). B) Provide data to the industry for the development of new smoke sensing technology. C) Provide data to the materials and additives industry to facilitate new smoke suppression technologies and improved end products. D) Provide education to the fire community. p/11

12 Technical Plan 1. Characterize samples Material chemistry: FTIR-ATR Physical construction: Density, Size, etc. Thermal properties: DSC, TGA 2. Evaluate material specific combustion properties for effects of material chemistry, physical construction, and combustion mode Ignition time, Heat and Smoke release rates, Weight consumption rate, Particle size and count distribution, Effluent gas: ASTM E1354 cone calorimeter coupled to particle and gas analyzers 3. Evaluate combustion properties for multi-component products Heat and Smoke release rates, Particle size and count distribution, Effluent gas: Intermediate-scale calorimeter coupled to particle and gas analyzers 4. Evaluate generated smoke and gases, alarm signal and response time in UL 217/268 Fire Test Room tests. p/12

13 Smoke Characterization Project: Findings Residential materials showed dramatically different heat and smoke release and smoke particle size behavior with non-flaming and flaming fires. Synthetic materials (e.g. polyethylene, polyester, nylon, polyurethane) generate higher heat and smoke release rates than the natural materials (e.g. wood, cotton batting). Flaming fires produce smaller mean smoke particles, non-flaming fires produce larger mean smoke particles. Photoelectric alarms triggered earlier for low-energy non-flaming fires. Ionization alarms triggered earlier for flaming and high-energy non-flaming fires. Smoke particles aggregate over time and distance from origin of ignition. Smoke from low energy, non-flaming fires may stratify as it rises and not reach to the ceiling. p/13

14 Smoke Characterization Project Sampling Method Calorimeter FTIR Every 15 s N 2 dilution Smoke Particle Every 67 s p/14

15 Particle density (1/cc) Smoke Characterization Project Smoke Particle Analyzer Data PET Carpet 1.3E E E E E E+00 Particle Size (nm) Time (s) p/15

16 Smoke Characterization Project Key Findings - Gas Analysis Smoke Gas Effluent Composition - Gas effluent analysis showed the dominant gas components were water vapor, carbon dioxide and carbon monoxide. Water CO 2 CO SO 2 NO 2 Methane Ammonia Phenol SiF 4 Formaldehyde HCN Propane HCl HF Ethylene Acrylonitrile Styrene p/16

17 General Smoke Characteristics Material Particle Size Particle Count Specific Extinction Area (Microns) (m 2 /g) (Total Smoke Gen. /weight loss) Cooking Oil/Lard.08 2E+6 (2 Million) >.7 Douglas Fir <.5E+5 <.35 Heptane/Toluene E E+6 <.35 Newspaper < 1E+6 <.35 Polyurethane Foam E+6 (F) 2.75E+6 (S).08 (F) -.9 (S) Ponderosa Pine < 1.5E+5 <.35 Human Hair During the various stages of a fire each material will generate unique particle sizes and count, and will generate different quantities of smoke. The response of an alarm will vary based on the material, and how it burns. p/17

18 Relative Signal Sensitivity Particle Size Influence on Sensing Technology Obscuration ~ d 3 Physics of ionization technology is linearly responsive to particle size. Physics of light-based technologies are more responsive to larger particles than smaller particles. Scattering ~ d 2 Ion ~ d d, Particle Size p/18

19 Smoke Detector Performance Smoke movement Smoke Stratification - Non-flaming fires result in changes in the smoke build up over time, such that stratification of smoke below the ceiling occurs. This time-dependent phenomenon results in less obscuration at the ceiling than below the ceiling. This caused both detection technologies to drift out of alarm. p/19

20 Smoke movement Key Findings - Fire Test Room Before Before After p/20

21 OBS (%/ft) Smoke movement 12 4 in below ceiling 24 in. below ceiling in. below ceiling 60 in below ceiling PU foam in Poly Time (sec) p/21

22 Material of Interest (STP follow-up activity) Polyurethane Higher heat release rate (flaming) Higher smoke release rate (smoldering) Smaller black particles (flaming) p/22

23 Polyurethane Flaming Fire Video p/23

24 New flaming & smoldering polyurethane tests: Develop new flaming and smoldering polyurethane (PU) foam fire tests to compliment existing UL 217 and 268 tests. Increase available egress time for non-specific fires by expanding alarm responsiveness to other smoke signatures. Rationale Flaming PU foam generates smaller smoke particles than the current fire tests. Synthetic materials generate greater heat and smoke release rates than natural materials. Prevalence of PU foam in residential settings (mattresses, upholstered furniture, etc.). p/24

25 Standard Foams Currently Used Product Test Method Foam Test Material Description Smoke detectors Upholstered furniture Residential sprinklers EN 54-7, ISO ASTM E 1353, CPSC 1634 CA TB117+, CPSC 1634 UFAC UL 1626 Soft polyurethane foam - No fire retardant - Density: c. 20 kg/m 3 SPUF: Polyurethane foam - No inorganic fillers or FR - Density: 28.8 ±1.6 kg/m 3 (1.8 ±0.1 lb/ft 3 ) SFRPUF: Flame-retardant polyurethane foam - Density: 22.4 ±1.6 kg/m 3 (1.4 ±0.1 lb/ft 3 ) Polyurethane foam - No inorganic fillers or FR - Density: 24.0 ± 1.6 kg/m³ (1.5 ± 0.1 lb/ft³) Polypropylene oxide polyol, polyether foam - Density: kg/m 3 ( lb/ft 3 ) - PHRR at 30 kw/m 2 : 230 ±50 kw/m 2 - HOC at 30 kw/m 2 : 22 ±3 kj/g p/25

26 Scenario Development Task Objectives: Investigate influence of scenario variables on combustion products. Develop smoke particle size and gas effluent data on the scenarios. Test Parameters: Variables Foam density Sample size & shape Heating method Output Smoke build-up rate p/26

27 Flaming Fire Scenarios Goal: Flaming foam test that achieves obscuration levels similar to the UL 217 flaming tests in a comparable time frame. Potential Scenarios: EN 54-7 TF 4 flaming foam test Variations in foam density, sample size & shape, ignition point p/27

28 Flaming Fire Scenarios Variables: Foam density Sample size & shape Ignition point 2 step burning process: Flame front Molten sample Completed: 26 Calorimeter tests 22 Fire Room tests Flame-out ranged from 260 to 2129 s 10 %/ft Obs reached in 85 to 1540s & never p/28

29 Polyurethane Flaming Test Sample p/29

30 Smoldering Fire Scenarios Goal: Smoldering foam test that: Achieves 10 %/ft obscuration at 45 min. Achieves %/ft obscuration by 60 min. Avoids settling/stratification (test < 75 min.). Potential Scenarios: Radiant panel: Heat from sample top surface Hot plate: Heat from sample bottom surface Cigarette ignition: Heat from sample top surface but covered Hot wire: Heat from sample center p/30

31 Smoldering Fire Scenarios Radiant Panel Variables: Fuel mass Rheostat level Completed: 22 Calorimeter tests 30 Fire Room tests 10 %/ft Obs reached 412 to 2936s & Never p/31

32 Smoldering Fire Scenarios Hot Plate Variables: Fuel mass Sample shape Heating profile Completed: 26 Calorimeter tests 10 Fire Room tests 10 %/ft Obs reached 1788 to 2620s & Never p/32

33 Obscuration (%/ft) Smoldering Fire Scenarios Hot Plate Lower obscuration observed for lower heating rates. F180 VF F125 Alt. 1 F125 Alt Time (s) p/33

34 Summary Gaps in previous research lead to Smoke Characterization Project. Smoke Characterization Project findings lead to work to improved response of alarms and detectors to nonspecific fires. UL is working with both national and international experts to address these issues. p/34

35 Smoke Characterization Research QUESTIONS Paul E. Patty, p/35