ordre de service · OS
Page approvedn. m. · site instruction · architect's instruction (UK) · notice to proceed (US, start) · ASI (US, change)
Definition
Document écrit par lequel la maîtrise d'œuvre donne une instruction à l'entreprise : démarrer les travaux, les arrêter, les reprendre ou les modifier. Il est numéroté, daté et notifié. Un ordre de service qui change le prix ou le délai doit ensuite être régularisé par un avenant.
A written document by which the design team gives an instruction to the contractor: start the work, stop it, resume it or change it. It is numbered, dated and notified. An order that changes the price or the time must then be regularized by a change order (avenant).
Example sentences
Written (email, official document)
FRL'ordre de service n° 3 demande à l'entreprise d'arrêter les travaux de la zone nord jusqu'à nouvel ordre.
ENInstruction no. 3 tells the contractor to stop work in the north area until further notice.
Spoken (standard)
FRJ'envoie l'OS de démarrage lundi, le chantier peut commencer le 15.
ENI'm sending the notice to proceed on Monday, work can start on the 15th.
Spoken (informal)
FRL'entreprise veut un OS pour ça, sinon elle ne touche à rien.
ENThe contractor wants a written instruction for that, otherwise they won't touch anything.
Nuances and pitfalls
A written order, not a phone call. On a French site, the contractor normally carries out changed or additional work only on a written ordre de service (n. m.) from the design team: that piece of paper protects everyone in a dispute.
Several kinds of OS. The start OS launches the works and starts the clock; later ones stop, resume or change the work. An OS that changes the price or the time must afterwards be covered by an avenant.
OS or avenant? An ordre de service is an order given by the design team, which the contractor carries out; an avenant is an agreement signed by both parties that changes the contract. When an OS changes the price or the time, the new amount or the new time is then set by an avenant.
Related terms
avenantmaître d'œuvrecompte renduDCEValidation
- French term, register, FR sentences : ✓ validated
- US/UK equivalents and EN sentences : ✓ validated
Reviewed by Raphaël B. · 7 Oct 2026
Spotted a mistake? Report an error in this entry
Free to use. Donations help cover hosting and the domain name. Support this site · French lessons for architects