NIST Report of Test FR 4020

Home Smoke Alarm Project, Alarm Response Calibrations
Report of Test FR 4020
December, 2003

Thomas G. Cleary
Building and Fire Research Laboratory
National Institute of Standards and Technology

This Report of Test presents data from a series of alarm response calibration tests as part of research into the performance of smoke alarms.

Introduction

The purpose of these tests was to provide a consistent calibration of all of the modified alarms used in the fire test series. The modified photoelectric and ionization alarms were exposed to smolder smoke and soot from a propene flame. CO alarms were exposed to smolder smoke that contained carbon monoxide. Full details on the alarm calibration procedures can be found in NIST Technical Note 1455 [1]. The alarm naming convention is described in NIST TN 1455, along with uncertainty estimates for each measurement.

Test Data

Each data file worksheet is identified as "Smolder" for smoldering smoke exposure and "Flame" for flaming soot exposure followed by a number incremented for repeated tests. A _s1, _s2, or s3 appended to the Smolder worksheet indicates it was used to generate the calibration equation for either test sequence 1 (SDC 1-15), test sequence 2 (SDC 20-28) or test sequence 3 (SDC30-41) respectively. In general, alarms were re-calibrated if they were used in a test sequence, or after they were repaired.

CO Alarms

CO Alarm Calibration Spreadsheet Files

The worksheet columns for CO alarms include:

• Time (s) = The time in seconds from the start of the test
• T (oC) = The FE/DE duct air temperature
• UL Transmittance = The FE/DE Upper Laser transmittance (1.52 m pathlength)
• CO-#-## (V) = The modified alarm voltage
• CO (V) = The carbon monoxide NDIR analyzer output voltage
• CO2(V) = The carbon dioxide NDIR analyzer output voltage
• Rel Humidity (%) = The FE/DE duct relative humidity
• BP (torr) = FE/DE Lab barometric pressure in torr
• Time (s) avg interval = This column contains blocks of time when nominally steady smoke production conditions existed. The next seven columns are the data points associated with these time blocks.
• CO-#-## (V) interval mean = Mean value of CO alarm voltage over the steady smoke time interval
• CO-#-## (V) interval mean SD = The standard deviation of the CO alarm voltage mean
• CO (V) interval mean = Mean value of NDIR analyzer voltage over the steady smoke time interval
• CO (V) interval SD = The standard deviation of the analyzer voltage mean
• Vol fraction (x10E-6) CO interval mean = Mean value of NDIR analyzer CO concentration over steady smoke time interval.
• Vol fraction (x10E-6) CO interval SD = The standard deviation of the analyzer CO concentration

Photoelectric Alarms

Photoelectric Alarm Calibration Spreadsheet Files 

The worksheet columns for Photoelectric alarms photo-1 and photo-3 include:

• Time (s) = The time in seconds from the start of the test
• T (deg C) = The FE/DE duct air temperature in oC
• UL Transmittance = The FE/DE Upper Laser transmittance (1.52 m pathlength)
• photo-#-## (volts) = The modified alarm voltage
• Rel Humidity (%) = The FE/DE duct relative humidity
• MIC (pA) = Measuring ionization chamber (MIC) current in picoamps
• BP (torr) = FE/DE Lab barometric pressure in torr
• Time (s) avg interval = This column contains blocks of time when nominally steady smoke production conditions existed. The next six columns are the data points associated with these time blocks
• photo-#-## (V) interval mean = Mean value of the photo alarm voltage over the steady smoke time interval
• photo-#-## (V) interval mean SD = The standard deviation of the photo alarm voltage mean
• MIC (pA) interval mean = Mean value the MIC current over the steady smoke time interval
• MIC (pA) interval SD = The standard deviation of the MIC current mean
• UL Trans. Interval mean = Mean value of the upper laser transmittance over the steady smoke time interval 
• UL Trans. Interval SD = The standard deviation of the upper laser transmittance
• Extinction (1/m) interval mean = Mean value of the extinction coefficient over the steady smoke time interval
• Extinction (1/m) interval SD = The standard deviation of the extinction coefficient
• Obs (%/ft) interval mean = Mean value of obscuration over the steady smoke time interval
• Obs (%/ft) interval SD = The standard deviation of the smoke obscuration

Ionization Alarms

Ionization Alarm Calibration Spreadsheet Files

The worksheet columns for Ionization alarms include:

• Time (s) = The time in seconds from the start of the test
• T (oC) = The FE/DE duct air temperature
• UL Transmittance = The FE/DE Upper Laser transmittance (1.52 m pathlength)
• ion-#-## (V) = The modified alarm voltage
• Rel Humidity (%) = The FE/DE duct relative humidity
• MIC (pA) = Measuring ionization chamber (MIC) current in picoamps
• BP (torr) = FE/DE Lab barometric pressure in torr
• Time (s) avg interval = This column contains blocks of time when nominally steady smoke production conditions existed. The next six columns are the data points associated with these time blocks.
• ion-#-## (V) interval mean = Mean value of the photo alarm voltage over the steady smoke time interval
• ion-#-## (V) interval mean SD = The standard deviation of the photo alarm voltage mean
• MIC (pA) interval mean = Mean value the MIC current over the steady smoke time interval
• MIC (pA) interval SD = The standard deviation of the MIC current mean
• UL Trans. Interval mean = Mean value of the upper laser transmittance over the steady smoke time interval. 
• UL Trans. Interval SD = The standard deviation of the upper laser transmittance
• Extinction (1/m) interval mean = Mean value of the extinction coefficient over the steady smoke time interval
• Extinction (1/m) interval SD = The standard deviation of the extinction coefficient
• Obs (%/ft) interval mean = Mean value of obscuration over the steady smoke time interval
• Obs (%/ft) interval SD = The standard deviation of the smoke obscuration
• Y interval mean = The ion alarm "Y" value computed from the alarm voltage signal over the steady smoke time interval
• Y interval SD = The ion alarm "Y" value standard deviation

Aspirated Alarms

Aspirated Alarm Calibration Spreadsheet Files

The worksheet columns for aspirated alarms include:

• Time (s) = The time in seconds from the start of the test
• T (oC) = The FE/DE duct air temperature
• UL Transmittance = The FE/DE Upper Laser transmittance (1.52 m pathlength)
• Asp-## (V) = The modified alarm voltage
• Rel Humidity (%) = The FE/DE duct relative humidity
• MIC (pA) = Measuring ionization chamber (MIC) current in picoamps
• BP (torr) = FE/DE Lab barometric pressure in torr
• Time (s) avg interval = This column indicates the time intervals of nominally steady smoke production that were specified to compute the mean values in the following columns.  
• Asp-## (V) interval mean = Mean value of the alarm voltage over the steady smoke time interval
• Asp-#-## (V) interval mean SD = The standard deviation of the alarm voltage mean
• UL Trans. Interval mean = Mean value of the upper laser transmittance over the steady smoke time interval. 
• UL Trans. Interval SD = The standard deviation of the upper laser transmittance
• Extinction (1/m) interval mean = Mean value of the extinction coefficient over the steady smoke time interval
• Extinction (1/m) interval SD = The standard deviation of the extinction coefficient
• Obs (%/ft) interval mean = Mean value of obscuration over the steady smoke time interval
• Obs (%/ft) interval SD = The standard deviation of the smoke obscuration

Acknowledgments

The home smoke alarm project was sponsored by the U.S. Consumer Product Safety Commission, Centers for Disease Control and Prevention, U.S. Fire Administration, and the U.S. Department of Housing and Urban Affairs, Underwriters Laboratories. The National Fire Protection Association (In-kind contribution), and National Research Council Canada, (In-kind contribution).

References

[1] Bukowski, R.W., Peacock, R.D., Averill, J.D., Cleary, T.G., Bryner, T.G., Walton, W.D., Reneke, P.A., and Kuligowski, E.D., Performance of Home Smoke Alarms: Analysis of the Response of Several Available Technologies in Residential Fire Settings, Natl. Inst. Stand. Technol., Tech. Note 1455 (2003).