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TECH SOLUTIONS 605.0Calculating Insulation Needs toFight Frost Heave by ComparingFreezing Index and Frost Depth

To calculate the amount ofinsulation needed to protect highways, railroads, airport run-ways, utility lines and buildingfoundations against frost heave,it’s important to know the amountof frost penetration. There are twoways to calculate frost penetration:theoretically or actual field moni-toring. Dow uses both methods.A theoretical formula that predictsfrost depth with freezing indexinformation provides a quick

estimate. Obtaining actual fielddata provides the most accurateinformation.

The freezing index is defined asthe number of degree-days(above and below 32°F [0°C])between the highest point in theautumn and the lowest point inthe spring on the cumulativedegree-day time curve for onewinter season. Or, simply the totalnumber of degree-days of freezingfor a given winter.

To help with calculations, thisinformation sheet includes:• maps of Canada showing

the normal (mean) value offreezing index

• listings of normal freezing indexdata for major areas acrossCanada

• charts showing the relationshipbetween freezing index andfrost penetration as preparedby the Ministry of Transportationof Ontario

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Chart 1Normal Freezing Index

in Degree-Days FahrenheitBased on the Period 1931 to 1960

Prepared jointly by the Division ofBuilding Research, NationalResearch Council, and the

Atmospheric Environment Service,Dept. of the Environment, Canada

Figure 1: Freezing Index Map for Canada

TECH SOLUTIONS 605.0

C A N A D A . G E O T E C H N I C A L I N F O R M AT I O N

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SOUTHERN ONTARIONormal Freezing Index in Degree-Days Celsius

Based on the Period 1931 to 1970Engineering Research andDevelopment Branch, MTC

NORTHERN ONTARIONormal Freezing Index in Degree-Days Celsius

Based on the Period 1931 to 1970Engineering Research andDevelopment Branch, MTC

Figure 2: Freezing Index Map for Southern Ontario

Figure 3: Freezing Index Map for Northern Ontario

Calculating Insulation Needs to Fight Frost Heave by Comparing Freezing Index and Frost Depth

TECH SOLUTIONS 605.0

C A N A D A . G E O T E C H N I C A L I N F O R M AT I O N

Calculating Insulation Needs to Fight Frost Heave by Comparing Freezing Index and Frost Depth

CLAY & DAMP TOP SOILSILT & SANDY SILTSILTY SAND

GLACIAL TILL

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Figure 4: Relationship between air freezing index, surface cover and frostpenetration into homogeneous soils

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Figure 5: Relationship between air freezing index, surface cover and frost penetration into a granular soil overlying a fine-grained soil

Figure 6: Frost Penetration in Ontario 1970-1975

Table 1: Freezing Indices for Canada

Freezing IndexStation Degree-Days °F Degree-Days °CBritish ColumbiaAbbotsford A(1) 45 25Beatton River A 3,893 2,164Comox A 596 331Cranbrook A 1,314 730Dog Creek A 1,457 809Fort Nelson A 4,523 2,513Fort St. John A 2,848 1,582Kamloops A 603 335Kimberley A 1,434 797New Westminister 35 19Penticton A 313 174Port Hardy A 33 18Prince George A 1,670 928Prince Rupert A 64 36Princeton A 1,111 617Quesnel A 1,457 809Sandspit A 35 19Smithers A 1,498 832Smith River A 4,866 2,703Terrace A 637 354Tofino A 20 11Vancouver A 31 17Victoria A 28 16Williams Lake A 881 489Yukon TerritoryAishihik A 5,038 2,799Dawson 6,174 3,430Haines Junction 4,498 2,499Mayo 5,454 3,030Snag A 6,477 3,598Teslin A 3,754 2,086Watson Lake A 3,281 1,823Whitehorse 3,574 1,986Northwest TerritoriesCape Dyer A 7,058 3,921Coral Harbour A 8,552 4,751Fort McPherson 7,747 4,304Frobisher Bay A 7,026 3,903Hay River A 5,512 3,062Inuvik A 8,424 4,680Norman Wells A 7,026 3,903Resolute Bay A 11,166 6,203Tuktoyaktuk 8,855 4,919Yellowknife A 6,506 3,614AlbertaBanff 1,963 1,091Calgary A 1,791 995Cold Lake A 3,174 1,763Cowley A 1,413 785Edmonton A 2,593 1,441Embarras A 4,439 2,466Fort McMurray A 4,024 2,236Grande Prairie A 2,967 1,648Jasper 1,885 1,047Lake Louise 2,810 1,561Lethbridge A 1,326 737Medicine Hat A 1,809 1,005Peace River A 3,805 2,114

(1) A indicates an airport data station.

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TECH SOLUTIONS 605.0Calculating Insulation Needs to Fight Frost Heave

by Comparing Freezing Index and Frost Depth

Table 1: Continued

Freezing IndexStation Degree-Days °F Degree-Days °CAlberta – continuedPenhold A 2,586 1,437Red Deer 2,382 1,323Suffield A 2,259 1,255Vermilion A 3,222 1,790SaskatchewanBroadview A 3,244 1,802Dafoe A 3,722 2,068Estevan A 2,646 1,470Moose Jaw A 2,555 1,419North Battleford A 3,378 1,877Prince Albert A 3,739 2,077Regina A 3,175 1,764Saskatoon A 3,284 1,824Swift Current A 3,323 1,846Uranium City A 5,551 3,084Yorkton A 3,563 1,799ManitobaBrandon A 3,388 1,882Churchill A 6,698 3,721Flin Flon 4,279 2,377Gimli A 3,417 1,898MacDonald A 3,038 1,688Neepawa A 3,282 1,823Portage La Prairie A 2,855 1,586Rivers A 3,315 1,842Winnipeg A 3,251 1,806OntarioAlgonquin Park 2,147 1,193Belleville 1,143 635Brampton 1,026 570Brantford 790 439Chalk River 2,096 1,164Chatham 531 295Cochrane 3,309 1,838Collingwood 975 542Dryden 3,395 1,886Georgetown 1,084 602Guelph 1,055 586Hamilton 663 368Huntsville 1,656 920Iroquois Falls 3,388 1,882Kapuskasing A 3,439 1,911Kenora A 3,172 1,762Kingston 1,220 678Kirkland Lake 3,244 1,802Kitchener 983 546Lindsay 1,445 803London A 863 479Moosonee 4,081 2,267Niagara Falls 684 380North Bay 2,210 1,228 Orangeville 1,423 791Orillia 1,495 831Ottawa A 1,829 1,016Owen Sound 995 553Parry Sound 1,517 843Peterborough 1,365 758Port Arthur (Thunder Bay) 2,541 1,412

Continued on next page

TECH SOLUTIONS 605.0Calculating Insulation Needs to Fight Frost Heave

by Comparing Freezing Index and Frost Depth

Freezing IndexStation Degree-Days °F Degree-Days °COntario – continuedSt. Catharines 506 281St. Thomas 710 394Sarnia 670 372Sault Ste. Marie A 1,663 924Simcoe 751 417Sioux Lookout A 3,450 1,917Stratford 1,072 596Sudbury A 2,401 1,334Timmins A 3,160 1,756Toronto 629 349Toronto A 897 498White River 3,344 1,858Windsor A 565 314Woodstock 929 516QuébecBagotville A 2,867 1,593Baie Comeau A 2,518 1,399Chicoutimi 2,536 1,409Drummondville 1,827 1,015Gagnon A 4,216 2,342Gaspé 2,012 1,118La Malbaie 2,043 1,135Mont Laurier 2,325 1,292Montréal A 1,583 879Québec 1,822 1,012Québec A 2,059 1,144Sept-Iles A 2,746 1,526Sherbrooke 1,581 878Sorel 1,997 1,109Tadoussac 2,038 1,132Three Rivers 2,139 1,188New BrunswickEdmundston 2,219 1,233Fredericton A 1,561 867Moncton A 1,397 776Pennfield Ridge A 1,178 654

Table 1: Continued Table 1: Continued

Freezing IndexStation Degree-Days °F Degree-Days °CNew Brunswick – continuedSackville 1,174 652St. George 1,115 619Saint John 1,002 557Saint John A 1,137 632Sussex 1,337 743Woodstock 1,701 945Nova ScotiaAnnapolis Royal 593 329Cheticamp 955 531Debert A 1,136 631Greenwood A 815 453Halifax 556 309Halifax A 856 476Ingonish Beach 828 460Liverpool 453 252Shearwater A 699 388Springfield 933 518Sydney A 811 451Truro 1,025 569Yarmouth A 415 231Prince Edward IslandAlliston 1,000 556Charlottetown A 1,201 667Summerside A 1,242 690NewfoundlandArgentia A 475 264Bonavista 853 474Buchans A 1,724 958Churchill Falls A 4,818 2,677Corner Brook 1,120 622Gander International A 1,207 671Goose A 3,268 1,816Grand Falls 1,394 774St. John’s 648 360Stephenville A 925 514Wabush Lake A 4,688 2,604

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Republished November 2008