Petie’s Comfort Level Scale

A Risk Assessment Tool fro HazMat Events

Scale                                 1                     2                      3                      4                     5

Risk Level                      Lowest              Low                Medium             High             Highest

Examples                              Powders/                 Heavy                  Lighter                     Liquids/                 Gases

                                                 Solids                     liquids                 liquids                     Vapors

Risk Factors

Physical parameters

State/matter released             solid                     liquids                   liquids                     liq/gas                  gas

Material temperature              room                      room                   +/- room                   hot/cold              extreme

Chain length                          v. long                      long                     medium                   short                  v.short

AMU molecule size                 huge                    large                    medium                    small                  v.small

NFPA reactivity #                    0 to 1                     0 to 1                    1 to 2                          2 to 3                      4

Boiling Point                           none                    very high                 moderate                   low                   very low

Corrosive/pH                          6 to 8                     5 to 9                      4 to 10                      3 to 11              <2, >12

Flash point                              none                    >140F                 100 – 140                   <100F                   <0 F

Flammable range                    none                   none                     small                        medium                wide

NFPA Flammability #              0 to 1                    0 to 1                    1 to 2                         2 to 3                      4

Ignition temperature                none                  very high             moderate                      low                    very low

Oxidizer class                         NFPA 1                 NFPA 2                NFPA 3                     NFPA 4               Org. Per.

Radiation                                 none                      none                  contained                    little                        yes

Vapor Density                          none                     heavy                  sl. heavy                     +/- air                     light

Vapor Pressure                        none                  very low                 <100                      100 to 760              >760

Is fire present?                           no                        no                         no                              near                      yes

Weather

Ambient Temperature           below fp               near fp                @flashpt                  above fp               much >fp

Humidity                                    low                        low                      moderate                   high                   very high

Time of day                              night                      night                   night/day                     day                     mid day

Wind                                           low                        light                    moderate                  high                    very high

Health

NFPA Health #                         0 to 1                   0 to 1                        1 to 2                  2 to 3                          4

TLV’s/PEL’s                             none                    high                      moderate                 low                       very low

IDLH                                          none                    high                      moderate                 low                       very low

EPA Signal word                     none                 caution                     warning                  danger                  poison

AEGL’s                                     none                    none                        none                     high                          low

People                                      none                      few                        some                   multiple                    many

Animals                                    few                     some                      multiple                   many                      many

Exposures                             minimal                small                       small                     multiple                  many

Container

Type                                          plastic                aluminum               light steel            med. steel              hvy. Steel

Insulated                                  none                     none                     carboy                 thermal                     cryogenic

Size/quantity                            small                   <5 gals                 <100 g                  <500 g                      >1000 g

Leak rate                                  none                      low                      moderate               heavy                         total

Damage to container             none                     little                      moderate                heavy                      catastr.

Impinged by fire?                       no                        no                            no                       near                           yes

Sampling results

Flammability                            none                      low                      10% LEL                <LEL                       >LEL

Oxygen                                     normal                <normal                 reduced               @19.5%                  <19.5%

Toxicity                                      none                  none/low                    low                      <TLV                         >TLV

Radiation                                 none                    none                     contained                 little                          yes

Corrosivity                               normal                  5 to 9                     4 to 10                 3 to 11                      <2, >12

Intangibles                               none                    few                          some                     multiple                  many

Back to Peterson Article