Appendix D: Revised Salt Treatment Matrix

Appendix D: Revised Salt Treatment Matrix

Weather Conditions
Road Surface Conditions
Road Surface Temperature (RST)

Air Temp

Treatment

 

 

Dry Salting (g/m2)

Pre-wetted Salting (g/m2) (see Note 1)

Ploughing

Frost or forecast frost

RST at or above -2oC

8

8

No

Frost or forecast frost

RST below - 2oC and above - 5oC and dry or damp road conditions (see Note 3 if damp and lightly trafficked)

10

9

No

Frost or forecast frost

RST below - 2oC and above - 5oC and wet road conditions (see Note 3 if lightly trafficked)

16

15

No

Frost or forecast frost

RST at or below - 5oC and above -10oC and dry or damp road conditions (see Note 3 if damp and lightly trafficked)

18

18

No

Frost or forecast frost

RST at or below - 5oC and above -10oC and wet road conditions (existing or anticipated) (see Note 3 if lightly trafficked )

2 x 15

2 x 15

No

Light snow forecast (<10mm)

20

18

No

Medium/heavy snow or freezing rain forecast

2 x 20

See Note 2 below

No

Freezing rain falling

20

(successive)

See Note 2 below

No

After freezing rain

20

See Note 2 below

No

Ice formed (minor accumulations)

above -5oC

20

See Note 2 below

No

Ice formed

at or below -5oC

2 x 20

See Note 2 below

No

Snow covering exceeding 30mm

20

(successive)

See Note 2 below

Yes

Hard packed snow/ice

above - 8oC

20

(successive)

See Note 2 below

No

Hard packed snow/ice

at or below - 8oC

salt/abrasive (successive)

See Note 2 below

No

Rate of spread for precautionary treatments may be adjusted to take account of residual salt or surface moisture unless stated otherwise within NMM 5.6.4 (AMM 36-02).

Notes:
1. Spread rates for pre-wetted salt is the combined weight of dry rock salt and brine combined at 70:30 proportion by weight respectively with a maximum brine concentration of 23% salt.
2. When ice has formed or snow is lying dry salting is the preferred treatment unless the road is closed to traffic when pre-wetted salting may be used. Pre-wetted salting is the preferred treatment in advance of such conditions.
3. Treatments should be carried out, whenever possible, after traffic has dispersed standing water. Successive half rate treatments (for both pre-wet and dry salt operations) should be considered for lightly trafficked roads at the lower end of temperature bands indicated

Published on behalf of the Scottish Salt Group by Transport Scotland,

Buchanan House,
58 Port Dundas Road,
Glasgow G4 0HF.

0141 272 7100

info@transportscotland.gsi.gov.uk
www.transportscotland.gov.uk