Pressure management in compartment fires (PAHAHUPA)


The research project PAHAHUPA investigates the fire-induced pressures and ventilation flows in compartment fires. The goals of the research project are

  • to find out how to simulate ventilation and leakage in compartment fires,
  • to learn how the tightening energy norms (air tightness) affect the pressures and possible risks, and
  • how the pressure effects can be managed.

Experimental characterization of fire-induced pressures in apartment

13 fire tests were carried out to in Kurikka, western Finland, in fall 2015. Two different fire sources (heptane pools, polyurethane foams) and three different ventilation arrangements (closed, open, normal) were studied. The figure below shows ventilation ducts in these configurations. Additional section of duct was used for instrumentation purposes.


Below are snapshots from a video showing how Pasi Paloluoma from the South-West Finland Rescue Services ignited the heptane pool fire. After the experiments, the team was relieved and happy.


Modelling and simulation of pressure and ventilation flows

In this task we learned how to simulate the development of pressure and flows in a typical ventilation system using the FDS. The main results are the guidance on how to model the compartment ventilation and leakage using the HVAC module of FDS, and the validation statistics using both our own data and literature data provided by the Swedish FOA institute.

See the master’s thesis of Rahul Kallada Janardhan for more information.

Case studies

Apartment building

The apartment building case study investigates the effect of the building envelop air-tightness on the pressures and smoke spreading in the ventilation network of a modern, mechanically ventilated apartment building.

See Umar Riaz’ Master thesis for more information.

Prison cell fire

The prison cell case study tries to evaluate the risks of a cell fire on the people inside the neighbouring cells, effectiveness of the different fire safety measures, and to provide guidance on the personnel.

Publications, talks and interviews

  1. Final Report has been published online.
  2. Fire-Induce Pressure and Smoke in Airtight Building. IAQ Magazine, Vol 1, Issue 03, Apr 2022.
  3. Master’s thesis of Umar Riaz
  4. Hostikka, S. Fire-induced pressure and smoke spread in airtight buildings. International Congress Fire Safety & Science. November 14 and 15, 2018. Arnhem, Netherlands.
  5. Hostikka, S., Janardhan, R.K., Riaz, U., Sikanen, T. Fire-induced pressure and smoke spreading in mechanically ventilated buildings with air-tight envelopes. Fire Safety Journal 91 (2017), 380-388. (Open access link)
  6. Janardhan, R., Hostikka, S. Experiments and Numerical Simulations of Pressure Effects in Apartment Fires. Fire Technology, 53, 1353–1377 (2017). (Open access)
  7. Master’s thesis of Rahul Kallada Janardhan
  8. Hostikka, S. Janardhan, R.K., Riaz, U. Fire-induced pressures in modern airtight apartment building. Nordic Fire & Safety Days 2017. 17-18.8.2017, Aalborg University.
  9. Hostikka, S. Paineenhallinta huoneistopaloissa – tutkimushankkeen tuloksia ja suosituksia. Palotutkimuksen päivät 2017. Pelastustieto, palontorjuntatekniikka (2017), pp. 41-44.
  10. Simo Hostikka’s interview for
  11. Talotekniikka -lehti
  12. Increased Fire-Induced Pressure in Airtight Buildings – New Risks for Evacuation &
    Smoke Management
    , Sustainable Fire Engineering -conference, Sep 30, 2016, Dublin.
  13. Presentation at FinnBUILD-messut, Oct 14, 2016
  14. Onnettomuuksien ehkäisyn opintopäivät, Palopäällystöliitto, Tampere, 9-10.11.2016
  15. FIRE MODELLING OF ENERGY-EFFICIENT APARTMENT BUILDINGS – Consideration of air-tightness and mechanical ventilation. Fire and Evacuation Modelling Technical Conference, Spain, 15-17.11.2016
  16. Paloseminaari 18, Paloturvallisuus ja standardointi. 10.2.2016, Helsinki.
  17. Lehtinen, K. Forskningsprojekt ”PAHAHUPA”: Tryckskillnader i bostadsbränder. Nordiska brandkonferens, 12-13.5.2016, Malmö. Nationellt forensiskt centrum.
  18. Hostikka, Janardhan, Experimental study of pressures in residential fires. Nordic Fire and Safety Days, Copenhagen, 2016.
  19. Janardhan, Hostikka. FDS Simulations of Compartment Fire Pressures. Nordic Fire and Safety Days, Copenhagen, 2016.

Research partners

Aalto_ENG_EN_21_RGB_1 stravent vtt kauriala turku



psr hagab rise

Posted by Simo Hostikka

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