SILICON†
| CAS # | 7440-21-3 |
|---|---|
| Formula |
Si |
| Synonyms |
elemental silicon |
| Physical description | Black to gray, lustrous, needle-like crystals. | ||
|---|---|---|---|
| Boiling point | 4271°F | Molecular weight | 28.1 |
| Freezing point/melting point | 2570°F | Vapor pressure | 0 mmHg (approx) |
| Flash point | Vapor density | ||
| Specific gravity | 2.33 at 77°F | Ionization potential | |
| Lower explosive limit (LEL) | Upper explosive limit (UEL) | ||
| NFPA health rating | NFPA fire rating | ||
| NFPA reactivity rating | NFPA special instruction | ||
| Vapor hazard ratio (VHR) | |||
| Historical exceedance percentage | |||
| Target organs | |||
| Analyte code (IMIS no.) | 2235 (total); request using analyte code 9135 | S120 (resp); request using analyte code 9130 | |
|---|---|---|---|
| Sampling group | |||
| Sampler/Sampling media | Tared low-ash 37 mm PVC filter, 5 microns [SLTC108] | Tared low-ash 37 mm PVC filter, 5 microns, preceded by 10 mm nylon Dorr-Oliver cyclone for respirable samples. [SLTC108] | |
| Sampling time* | 240-480 min |
240-480 min |
|
| Sampling volume (TWA)* | 960 L |
816 L |
|
| Sampling flow rate (TWA)* | 2 L/min |
1.7 L/min ±5% |
|
| Sampling volume (STEL/Peak/C)* | |||
| Sampling flow rate (STEL/Peak/C)* | |||
| Analytical method instruments | Gravimetric | Gravimetric | |
| Method reference | OSHA PV2121 (partially validated) | OSHA PV2121 (partially validated) | |
| Notes | If the net weight of the sample yields a concentration below the PEL after considering the associated SAE , the SLTC will perform no further work on the sample and the sample air concentration will be reported as the calculated gravimetric air concentration. If the net weight corresponds to an amount greater than the PEL value after considering the associated SAE, the sample may be analyzed for the applicable component and appropriate results will be reported. |
If the filter is not overloaded, samples can be collected up to an 8-hour period. If the net weight of the sample yields a concentration below the PEL after considering the associated SAE , the SLTC will perform no further work on the sample and the sample air concentration will be reported as the calculated gravimetric air concentration. If the net weight corresponds to an amount greater than the PEL value after considering the associated SAE, the sample may be analyzed for the applicable component and appropriate results will be reported. |
|
| Special requirements | FOR TOTAL DUST SAMPLES, DO NOT USE A CYCLONE!! |
* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.
| Wipe Sampler/Sampling media | |
|---|---|
| Bulk Method |
| Device | |||||
|---|---|---|---|---|---|
| Model/Type | |||||
|
Sampling information (see manufacturer instructions) |
|
OSHA PEL
8-hour TWA (ST) STEL (C) Ceiling Peak |
NIOSH REL
Up to 10-hour TWA (ST) STEL (C) Ceiling |
ACGIH TLV©
8-hour TWA (ST) STEL (C) Ceiling |
|||||
|---|---|---|---|---|---|---|---|
| PEL-TWA |
15 mg/m³ (total dust), 5 mg/m³ (respirable fraction) |
REL-TWA |
10 mg/m³ (total dust), 5 mg/m³ (resp) |
TLV-TWA | PEL-TWA |
10 mg/m³ (total dust), 5 mg/m³ (respirable fraction) |
|
| PEL-STEL | REL-STEL | TLV-STEL | PEL-STEL | ||||
| PEL-C | REL-C | TLV-C | PEL-C | ||||
| Skin notation |
N |
Skin notation |
N |
Skin notation |
N |
Skin notation |
N |
| Notes: | Notes: |
Notes:
Not established; see individual compounds and/or Appendix B of the TLV booklet for guidelines. |
Notes:
As Particulates not otherwise regulated, see footnote [n]. |
||||
| Health factors: See NIH-NLM PubChem. | IDLH | ||||||
| Carcinogenic classifications: Not listed | Notes: | ||||||
| AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3: | |||||||
Additional Resources and Literature References
|
NOAA: CAMEO Chemicals - Silicon powder, amorphous NIOSH: Pocket Guide to Chemical Hazards - Silicon Literature References
|
Last Updated Date : 01/12/2021