3. Wind resistance

There are three performance criteria (see [C 3 610] , § 1.3.2.1):

• stiffness under pressure + p ₁ and – p ₁ ;

• the retention of initial performance after loading under a strain pressure of + p ₁ and – p ₁ and after loading for 50 cycles at – p ₂ and + p ₂ ;

• safety after conventional gust pressure loading + p ₃ and – p ₃ ....