Informations

What is the standard for my project?

The decree on standardisation states that standards are voluntary: they are contractual documents.

CTS regulation

The stability of ERP CTS event tents is calculated for a maximum wind speed of 100km/h and 15kg/m² of snow. Beyond that, the structure must be evacuated.

The CTS regulation only concerns establishments open to the public and has no significance on an industrial project.

NV65 calculation rules

The NV65 calculation rules define the effects of snow and wind on built structures.

Their purpose is to determine the values of climatic loadings for all the sites across the country as well as methods of evaluation and calculation of the corresponding forces on the whole of a construction.

Unlike the CTS regulations or the EN13782 standard, the application of NV65 rules to the dimensioning of the frame and the equipment of your building makes it possible to guarantee continuous exploitation, in conditions of safety identical to those of a traditional building.

Standard EN13782

This is a European standard that specifies the safety requirements to be observed in the design, calculation, manufacture, installation and maintenance of temporarily installed mobile tents with a floor area greater than 50 m2.

The reference snow weight is 20 kg/m². Beyond this, it is obligatory to carry out snow removal by heating, for example.

The reference wind speed is 28 m/s or 100.8 km/h. Above 100.8 km/h the calculation must incorporate Eurocode 1 (French Standard EN 1991-1-4) referenced below.

Eurocode 1

Eurocode 1 defines the general principles for calculating and loading of structures to be built. In France it is transcribed into the NF EN 1991-1-3/NA standard for snow and EN 1991-1-4 for wind.

It takes into account geographical specificities.

For the wind it considers 4 zones from 1 to 4; each zone being assigned a reference speed (149.1 km/h in zone 2, 166.6 km/h in zone 3 normal site and 186.3 km/h in exposed zone).

In addition, it provides coefficients for reducing or increasing the stress as a function of the exposure (or ruggedness) of the installation site.

For the snow it considers 8 zones (A1, A2, B1, B2, C1, C2, D and E).

Does the statement of wind resistance of 160km/h in a document guarantee the resistance of my structure?

A simple statement of wind speed resistance in no way characterises the conformity of the building with the NV65 or Eurocodes calculation rules. It is indeed important to check that the resistance stated is indeed that in force on your installation site.

This also applies to snow loading as well to additional assumptions, such as the exposure of your site (by the sea for example) or its altitude. Altitude is an aggravating factor for snow conditions: it must be clearly stated in writing in the assumptions taken into account.

In the case of Eurocodes, the ruggedness of the site must also be specified.

Is the statement of a building compliant with the NV65 or Eurocodes regulations in a technical or commercial document a guarantee of safety?

Yes, as long as the customer can ensure that the hypotheses of climatic loadings of its zone are indeed taken into account in the dimensioning of the structure. Only a written confirmation of snow and wind loads and aggravating factors such as altitude, distance to the sea and ruggedness makes it possible to ensure that they are taken into account in the calculations.

How then is it possible to evaluate respect of NV65 rules or Eurocodes with certainty?

The first thing is to ask your service providers for a calculation note of the work.

The only infallible approach is to consult a technical control office to validate the cold strength of the structure and to issue a report on the calculation note per finite element.

Some parameters can provide indicators:

• the size and section of the profiles used for the framework, which may be obviously insufficient
• the ground anchoring techniques and the joining of structural components, which indicate whether the main forces that applied to the frame have been treated
• the absence of reference to NV65 rules or Eurocodes and the calculation of frameworks in technical and commercial documents