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Repairs and other measures after investigations

Repairs or other measures can be implemented quickly if considered necessary based on the results of the indoor air investigations, in order to allow for continued use of the space. Below, we have listed a few examples on relatively quick measures for improving indoor air.

1. Measures by building services:

  • adjusting the temperature of input air and changing the scheduled times of ventilation
  • adjusting the radiator system, bleeding the radiators when necessary
  • opening blocked drains.

2. Measures by maintenance services:

  • cleaning the ventilation system
  • adjusting the quantity of air
  • removing the fibre sources of the ventilation system
  • water damage repairs and other small-scale repairs.

3. Measures by the division using the premises:

  • more efficient cleaning/removal of accumulated dust from high surfaces
  • relocation of furniture/decluttering
  • cutting the number of users in the premises
  • ventilation through windows to improve air flow.

In addition to the measures presented above, air purifiers can be procured for the premises in accordance with the City’s air purifier guidelines.

When the indoor air investigation has been completed, the repair measures will be decided on. The necessary repairs may be targeted at the entire building, a part of it, or a technical system like ventilation. Planning extensive repairs takes time. Some repairs may also require a building permit.

The primary method of repair is to remove the cause of the damage and fix the damage, as well as repairing or replacing faulty equipment. The possibility of using the premises during the repair work will always be reviewed on a case-by-case basis. Sometimes, operations need to be moved to temporary facilities either completely or partly.

The City of Helsinki always draws up a project plan for repairs costing more than €500,000. If the costs of a repair project are at least one million euro, the project plan must be approved by the Buildings and Public Areas sub-committee of the Urban Environment Division.

Indoor air repairs can be e.g.

1. limited repair projects:

  • a local repair of moisture damage
  • improvements to the entire building’s ventilation and building automation.

2. postponing repair projects before renovations:

  • additional sealing work
  • depressurising the crawl space and/or premises removed from use
  • over-pressurising the building/premises
  • installing ventilation machines in spaces.

3. renovations of the entire building.

Examples of repair measures

If the indoor air problems are caused by fibre sources in the silencer of the ventilation system, for example, the materials for the silencers are replaced or coated.

Sealing repairs are made if, for example, removing microbe damage from structures is not possible due to matters such as the damage’s location or causes related to the building’s protection measures. Sealing repairs are also performed as urgent measures that help secure the premises’ use. Sealing repairs of structures will prevent the contaminants from entering the indoor air. Sealing repairs are designed and implemented carefully, and usually their success is proven through tracer tests.

In addition to sealing the structures, a damaged structure or space can be depressurised. This means that the pressure ratios are adjusted in a way that prevents the air flow from the damaged section to the surrounding premises. Depressurisation can be used in crawl spaces below a building, or in pipe tunnels under a floor, for example.

Sometimes, renovation or modernisation is needed

In some cases, problems may be so extensive that complete renovation or modernisation of the building may be necessary. Renovation means that the building or an individual space or structure within the building is repaired to be as good as new. Modernisation, on the other hand, raises the quality level of the building to above that of the original building in some essential way.

The users of a building must usually be moved to temporary facilities for the duration of renovations, modernisation or other extensive repairs. The planning and implementation of a modernisation project may take several years.

Monitoring the repairs

The success of the repairs can be monitored after the repairs by taking dust samples from surfaces, for example, or by measuring the pressure ratios of the building or chemical contaminants in indoor air. If the indoor air quality in the premises is still considered inadequate after the repairs, it must be ensured whether all the necessary measures have been carried out.

In case of difficult problems, some of the people with the worst exposure may not be able to return permanently to the building even after it has been repaired.



27.08.2021 15:05