C.M.R. 06, 096, ch. 409, app 096-409-A
This document describes the preparation of a 5-point odor intensity referencing scale in general conformance with the static-scale method outlined in ASTM Standard E544 - 10 "Standard Practices for Referencing Suprathreshold Odor Intensity," ASTM International, West Conshohocken, PA, 2010, DOI: 10.1520/E0544-10, www.astm.org. This document is not intended to address user health and safety practices associated with the preparation of the odor intensity referencing scale. The appropriate health and safety resources should be consulted, and recommended guidelines followed, during scale preparation.
The scale is prepared with the reference odorant n-butanol (n-BuOH) in accordance with the concentrations specified in Table 1. Supporting rationale for the selection of n-butanol as the reference odorant is summarized in Appendix X1 of ASTM E544.
Table 1: 5-Point Odor Intensity Referencing Scale
| Level | n-butanol Concentration in Water (ppm) |
| 1 | 150 |
| 2 | 300 |
| 3 | 600 |
| 4 | 1200 |
| 5 | 2400 |
The scale ranges from 1 to 5. Level 1 consists of 150 parts per million (ppm) of n-butanol in distilled water. Subsequent levels (Levels 2 through 5) increase by a factor of 2 based on a volume to volume basis.
Level 1 - Jar 1: 150 ppm n-BuOH
Using a 1 milliliter (mL) pipet, measure 150 microliters (µL) of n-BuOH and add to 1,000 milliliter (mL) volumetric flask. Add distilled water to the 1,000 mL mark. Replace top and shake to mix. Use approximately 200 mL of the solution for Jar 1.
Level 2 - Jar 2: 300 ppm n-BuOH
Using a 1 mL pipet, measure 300 µL of n-BuOH and add to 1,000 mL volumetric flask. Add distilled water to the 1,000 mL mark. Replace top and shake to mix. Use approximately 200 mL of the solution for Jar 2.
Level 3 - Jar 3: 600 ppm n-BuOH
Using a 1 mL pipet, measure 600 µL of n-BuOH and add to 1,000 mL volumetric flask. Add distilled water to the 1,000 mL mark. Replace top and shake to mix. Use approximately 200 mL of the solution for Jar 3.
Level 4 - Jar 4: 1200 ppm n-BuOH
Using a 1 mL pipet measure 1 mL of n-BuOH and add to 1,000 mL volumetric flask; next using a 1 mL pipet measure 200 µL of n-BuOH and add to the 1,000 mL volumetric flask for a total of 1200 µL of n-BuOH. Add distilled water to the 1,000 mL mark. Replace top and shake to mix. Use approximately 200 mL of the solution for Jar 4.
Level 5 - Jar 5: 2400 ppm n-BuOH
Using a 2 mL pipet measure 2 mL of n-BuOH and add to 1,000 mL volumetric flask; next using a 1 mL pipet measure 400 µL of n-BuOH and add to the 1,000 mL volumetric flask for a total of 2400 µL of n-BuOH. Add distilled water to the 1,000 mL mark. Replace top and shake to mix. Use approximately 200 mL of the solution for Jar 5.
1Adapted from Tech Environmental, Odor Intensity Referencing Scale, Preparation of Samples for Static-Scale Method.
C.M.R. 06, 096, ch. 409, app 096-409-A