This document specifies the process for creating a cleanroom from requirements through to its design, construction and start-up. It applies to new, refurbished and modified cleanroom installations. It does not prescribe specific technological or contractual means of achieving these requirements. It is intended for use by users, specifiers, designers, purchasers, suppliers, builders and performance verifiers of cleanroom installations. The primary cleanliness consideration is airborne particle concentration. Detailed checklists are provided for the requirements, design, construction and start-up, which include important performance parameters to be considered. Energy management design approaches are identified to support an energy-efficient cleanroom design. Construction guidance is provided, including requirements for start-up and verification. A basic element of this document is consideration of aspects, including maintenance, that will help to ensure continued satisfactory operation for the entire life cycle of the cleanroom. NOTE       Further guidance is given in Annexes A to D. ISO 14644-1, ISO 14644-2, ISO 14644-8, ISO 14644-9, ISO 14644-10, ISO 14644-12 and ISO 14644-17 provide complementary information. ISO 14644-7 offers guidance on design, construction and requirements for separative devices (clean air hoods, glove boxes, isolators and mini-environments). The following subjects are mentioned but not addressed in this document: —    specific operational activities, processes to be accommodated and process equipment in the cleanroom installation; —    fire and safety regulations; —    ongoing operation, cleaning and maintenance activities, which are covered by ISO 14644-5.