One major cause of complications during the handover of a newly constructed cleanroom is not having a clear post-construction cleaning scope of works (SOW). Builders are responsible for delivering the facility cleaned, ready to meet a certain standard, but you as the room owner are responsible for these contaminants being removed prior to certification. Failing to eliminate particles and residue generated during the construction phase could result in these contaminants remaining in the environment for years to come. Just cleaning away visible debris is not sufficient for a cleanroom clean. Particles must be removed to the sub-micron level (smaller than the eye can see). Builders, along with general cleaners, lack the specialist cleanroom cleaning expertise, methods and equipment necessary to clean surfaces to the required ISO Class level. By using incorrect equipment, they could possibly even damage cleanroom surfaces and make them more likely to harbour bacteria and particulates. What can you do to minimise the risk of a less-than-successful post-construction clean?
A builder needs to work with someone familiar with cleanroom cleaning who can develop an SOW specifically for post-construction cleaning. Because you have the ultimate responsibility for production in the room, which also incorporates cleanliness, you need to review and approve this document. This SOW differs from the standard operating procedures written by facility staff for a fully operational cleanroom. In a post-construction clean, a two- and sometimes three-stage procedure is required, depending on the ISO Class of the room. The first phase focuses on removing gross contamination left from construction. The second (and possibly third) phase addresses fine contaminants and prepares the facility for pre-validation and sterile cleans. Although it is no replacement for full ISO certification, an air particle report made using a hand-held particle counter is a useful guide as to whether a post-construction clean has achieved the desired ISO Class particle results.