HYDROGEN CYANIDE (HCN) MONITORING Flashcards
HYDROGEN CYANIDE (HCN) MONITORING
HCN is produced by the burning of materials including:
o Wool o Cotton o Nylon o Plastic o Foam o Synthetic rubber
HYDROGEN CYANIDE (HCN) MONITORING
What are the properties of HCN? (10 things)
o Lighter than air o Colourless gas o Blueish-white liquid o Bitter almond odour o Combustible o Will rise in the heated environment of a structure fire o Vapours will linger in unventilated environment o Inhalation hazard o Skin absorption hazard o Half-life of 1 hour
HYDROGEN CYANIDE (HCN) MONITORING
HCN IDLH = ?
HCN STEL = ?
IDLH 50 ppm
STEL 4.7 ppm
STEL is defined as a 15 minute Time Weighted Average (TWA) exposure that shall not be exceeded at any time during a work day
HYDROGEN CYANIDE (HCN) MONITORING
What is considered Acute Exposure?
What is considered Increasing Levels?
Acute Exposure 5-10 ppm
Increasing Levels 25-50 ppm
HYDROGEN CYANIDE (HCN) MONITORING
HCN levels are fatal at:
- ? ppm after 30 minutes
- ? ppm after 10 minutes
- ? ppm after 6-8 minutes
HCN levels are fatal at:
- 135 ppm after 30 minutes
- 181 ppm after 10 minutes
- 270 ppm after 6-8 minutes
HYDROGEN CYANIDE (HCN) MONITORING
Peak levels of HCN shall be recorded on the HCN monitoring log sheet. Who do you send copies of the log sheet to?
- A copy will be forwarded to the Training Division for tracking purposes
- A copy will be forwarded to Administration included with other incident documents
HYDROGEN CYANIDE (HCN) MONITORING
Which trucks carry HCN detectors?
o Squads – 6
o H101 – 2
o P109 – 1
o P114 – 1
HYDROGEN CYANIDE (HCN) MONITORING
HCN monitoring shall be conducted during the following 4 conditions:
o All structure fires
o Vehicle fires within a structure or parking garage
o Cooking fires where there is damage to the container and the surrounding area
o All smoke investigations or unknown odour incidents
HYDROGEN CYANIDE (HCN) MONITORING
All firefighters exiting the hazard zone will:
o Remain on air for 2 minutes to off-gas PPE naturally
o Report to the decon area
o Decontaminate immediately with a light fog spray from the 45 mm hand line if low air prevents two minutes of off-gassing
HYDROGEN CYANIDE (HCN) MONITORING
After exiting the Hazard Zone and off-gassing for 2 minutes, your gear shall be monitored for HCN, if your reading is higher than ? ppm, a hose line set to light fog and PPV fan shall be used to decontaminate
o Firefighter shall stand ? metres from the PPV fan for passive air flow
2.5 ppm
3 metres
