NFPA 270, Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber

NFPA^® 270 Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber, 2023 Edition

Chapter 1 Administration

1.1 Scope.
1.2 Purpose. (Reserved)
1.3 Application.
1.4 Units and Formulas.

Chapter 2 Referenced Publications

2.1 General.
2.2 NFPA Publications. (Reserved)
2.3 Other Publications.
2.4 References for Extracts in Mandatory Sections. (Reserved)

Chapter 3 Definitions

3.1 General.
3.2 NFPA Official Definitions.
3.3 General Definitions.

Chapter 4 Test Apparatus

4.1 General.
4.2 Test Chamber.
4.3 Sample Support and Heating Arrangements.
4.4 Gas Supply.
4.5 Photometric System.
4.6 Chamber Leakage.
4.7 Cleaning Materials.
4.8 Ancillary Equipment.

Chapter 5 Test Environment

5.1 Light Interference.
5.2 Product of Combustion Venting.
5.3 Operator Safety.

Chapter 6 Test Specimen

6.1 Suitability of Sample for Testing.
6.2 Sample Face.
6.3 Number of Specimens.
6.4 Additional Specimens.
6.5 Size of Specimens.
6.6 Specimen Preparation.
6.7 Wrapping of Specimens.

Chapter 7 Setup, Calibration, and Maintenance

7.1 Setup and Calibration Procedures.
7.2 Alignment of Photometric System.
7.3 Selection of Compensating Filter(s).
7.4 Linearity Check.
7.5 Calibration of Range-Extension Filter.
7.6 Chamber Leakage Rate Test.
7.7 Burner Calibration.
7.8 Radiator Cone Calibration.
7.9 Cleaning.
7.10 Frequency of Checking and Calibrating Procedures.
7.11 Total System.

Chapter 8 Conditioning

8.1 Pre-Test.
8.2 Conditioning.

Chapter 9 Test Procedure

9.1 Initial Conditions.
9.2 Tests with Pilot Flame.
9.3 Preparation of Photometric System.
9.4 Loading Specimen.
9.5 Recording of Light Transmission.
9.6 Observations.
9.7 Termination of Test.
9.8 Specimen Mass.
9.9 Repeat Tests.

Chapter 10 Calculations

10.1 Specific Optical Density, Ds.
10.2 Clear Beam Correction Factor, Dc.
10.3 Mass Loss.

Chapter 11 Test Report

11.1 Descriptive Information.
11.2 Test Results.

Annex A Explanatory Material
Annex B Precision and Bias
Annex C Interlaboratory Application
Annex D Determination of Mass Optical Density
Annex E Informational References

2018 Edition

Essential for fire test labs and manufacturers, up-to-date testing criteria in new NFPA 270 helps users evaluate the extent of smoke obscuration.

NFPA 270, Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber provides a means of measuring smoke obscuration of essentially flat materials, products, or assemblies (including surface finishes) up to 25mm thick, when exposed to specified levels of thermal irradiance in a single closed chamber. This test method is based on ISO 5659-2, Determination of Specific Optical Density by a Single-Chamber Test, and provides equivalent results to ISO 5659-2.

The principal fire-test-response characteristic obtained from using NFPA 270 is the specific optical density of smoke from the specimens tested.

An optional fire-test-response characteristic measurable with this method is the mass optical density, which is the specific optical density of smoke divided by the mass lost by the specimens during the test.

The 2018 edition updates the pressure sensor requirements to reflect modern technology.

Other changes included references to other codes and standards. (Print, 40 pp., 2018)

2013 Edition

Evaluate the extent of smoke obscuration with the up-to-date testing criteria in the 2013 NFPA 270.

NFPA 270: Standard Test Method for Measurement of Smoke Obscuration Using a Conical Radiant Source in a Single Closed Chamber provides fire test labs and manufacturers with a means of measuring smoke obscuration of essentially flat materials, products, or assemblies (including surface finishes) up to 25mm thick, when exposed to specified levels of thermal irradiance in a single closed chamber. This test method is based on ISO 5659-2, Determination of Specific Optical Density by a Single-Chamber Test, and provides equivalent results to ISO 5659-2.

The principal fire-test-response characteristic obtained from using NFPA 270 is the specific optical density of smoke from the specimens tested. An optional fire-test-response characteristic measurable with this method is the mass optical density, which is the specific optical density of smoke divided by the mass lost by the specimens during the test.

The 2013 NFPA 270 includes updated code and standard references as well as editorial revisions that improve usability and consistency with other standards. (Softbound, 29 pp., 2013)

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