Construction according to the P1 purity class
In Finland the purity class P1 of the construction project aims to ensure that the premises of the finished building are clean when it is handed over to the customer. At the same time, impurities from the construction phase are prevented from entering the indoor air during the use of the building. When a developer aims for the S1 or S2 indoor air quality class, the project must be carried out in accordance with the so called P1 purity standards. P1 construction is not difficult as long as you know what you are doing.
The developer sets indoor air quality targets for the construction project. He/she presents the solutions designed to reach the goal to the designer and contractor at the site start-up meeting.
The main contractor must make a project-specific P1 dust control plan. Its goal is to improve dust control at the site. The plan takes into account the above requirements for indoor air quality and purity of construction work. It describes the principles and practices of dust control and guides the work of all site contractors. Training will ensure that the main components of P1 construction are considered.
The work supervisor must guide the construction work, cleaning and storage of the materials so that the purity requirements are met.
Stages of P1 purity class construction
Dust is prevented by active dust control, such as a source extraction devices or a dust control work station, like Consair CAMU. Dust and contaminants are controlled at the site when and where they are formed. The dust is picked up before the small and dangerous particles in it spread to tarnish the work space. At the same time, their access to the breathing air of the worker and thus to the alveoli is prevented.
The spreading of dust that has become air-borne despite the active dust control methods is managed by passive dust control. Mechanical ventilation is closed and ducts in work areas are blocked. Containment zones and negative pressure are key to passive dust control. Negative pressure units with HEPA filters are used. The dust content of the space can be controlled by air purifiers.
Construction materials are protected against moisture and contamination during transportation, intermediate storage and installation.
Construction site cleaning
Cleanliness is maintained regularly by cleaning. The brush must not be used in the P1 class, only scrapers and vacuum cleaners. Waste material is sorted at the place of origin in waste bins or sacks, which should be transferred to the waste collection point as dustless as possible. From now on, the site must be kept at the P1 purity level. Read more about P1 class cleaning.
Before the subscriber receives the complete building, the level of purity that the subscriber originally set as the target when they started the project must be attained in the final cleaning.
Assessment of purity
Before the building is handed over, all visible surfaces and interior surfaces of the furnishings are evaluated. Threshold values of 1–5% are set for allowed dust deposits.