NV 65 snow and wind rules

The gradual introduction of European regulations for both structural and action Eurocodes is having a major impact on the French standards environment, due to the new "philosophies" of approach on which they are based.

There is also the problem of compatibility between European regulations and those currently in force in France.

In France, rules defining the effects of snow and wind on buildings have been in force since 1965 (NV 65 rules).

Although these rules have already been updated, particularly in terms of zoning for snow action, it was necessary to take advantage of the numerous meteorological measurements and observations made since that date, and to update these rules accordingly. The NV 65 rules continue to apply to buildings whose materials do not have limit-state dimensioning rules.

The texts currently available in France for determining the actions of snow and wind on buildings are as follows:

NV 65 rules (Afnor reference DTU P 06-002) accompanied by :

• amendment no. 2 of December 1999 concerning the wind map ;

• modificatif n 3 d'avril 2000 relatif aux charges de neige.

Rules N 84 of September 1996 accompanied by :

• modification no. 1 of April 2000 (Afnor reference DTU P 06-006).

XP ENV 1991-2.3, October 1997

Eurocode 1: Design bases and actions on structures and national application document.

Part 2.3. – Actions on structures. Snow loads.

ENV 1991-2.4

Eurocode 1: Design bases and actions on structures.

Part 2.4. – Actions on structures. Wind action (national application document DAN under development).

The NV 65 rules set the values for snow and wind loads, and enable us to evaluate the corresponding forces acting on the structure of a building.

Drafted in 1965, they were the subject of appendices, revisions and addenda in 1967, 1970, 1975, 1976, 1985 (snow map), 1996 (snow map), 1999 (wind map) and 2000 (snow accumulation).

Amendments 2 and 3 to the NV 65 rules are an attempt to harmonize these various texts, both in terms of zoning for the French territory and French overseas departments and territories for snow and wind actions, and in terms of taking account of snow accumulation phenomena on roofs.

Finally, it should be remembered that the Eurocodes, which are national application documents (DAN), are only applicable if explicit reference is made to them:...