CARRIAGEWAY ICE PROCEDURES

Orkney Islands Council Winter Service Policy 2026 - 2031

Appendix 1C

1. START

2. Is Ice present or forecast?

   • Forecast: Appendix 1A Day or 1B Night
   • Present: What is the estimated thickness?

3. What is the estimated thickness?

   • ≤1mm: Lower of air or road surface temperature
     • Above -5ºC: 40 g/m2 Dry salt
     • At or below -5ºC: 40 g/m2 Dry salt/abrasive mix 50:50
   • 1-5mm: 40 g/m2 Dry salt/abrasive mix 50:50
     • Is traffic breaking up layer?
       • Yes: Appendix 1A Day or 1B Night
       • No: Successive treatment of 20 g/m2 Dry salt/abrasive mix 50:50
   • >5mm: 40 g/m2 Abrasive only
     • Is traffic breaking up layer?
       • Yes: 20 g/m2 Dry salt/Abrasive mix 50:50, then Appendix 1A Day or 1B Night
       • No: Successive 20 g/m2 Abrasive only; reassess whether traffic is breaking up the layer

IMAGE: Flowchart titled “CARRIAGEWAY ICE PROCEDURES” from the Orkney Islands Council Winter Service Policy 2026 - 2031, Appendix 1C. It begins with “START” and asks “Is Ice present or forecast?” A forecast leads to “Appendix 1A Day or 1B Night.” If ice is present, the chart asks “What is the estimated thickness?” For ice of “≤1mm,” it asks for the “Lower of air or road surface temperature”: above -5ºC leads to “40 g/m2 Dry salt,” while at or below -5ºC leads to “40 g/m2 Dry salt/abrasive mix 50:50.” For ice of “1-5mm,” the treatment is “40 g/m2 Dry salt/abrasive mix 50:50,” followed by “Is traffic breaking up layer?” A “Yes” answer leads to “Appendix 1A Day or 1B Night,” and “No” leads to “Successive treatment of 20 g/m2 Dry salt/abrasive mix 50:50.” For ice of “>5mm,” the treatment is “40 g/m2 Abrasive only,” followed by “Is traffic breaking up layer?” A “Yes” answer leads to “20 g/m2 Dry salt/Abrasive mix 50:50,” then “Appendix 1A Day or 1B Night.” A “No” answer leads to “Successive 20 g/m2 Abrasive only,” after which the traffic condition is reassessed.