(71q) Lessons Learned during Air Tightness Testing of Shelter-in-Place Buildings at Chemical Facilities

When properly implemented, the shelter-in-place building concept can protect personnel during a toxic gas release at a chemical manufacturing facility sufficiently and long enough for the event to pass, for occupants to don appropriate PPE and evacuate, or for a rescue to be coordinated by emergency responders. There are many issues to consider when assessing if such a building is suitable as a shelter-in-place for toxic hazards. While quantitative physical characteristics, such as the air tightness of the building envelope and the HVAC design, are key parameters to consider, more qualitative aspects such as written procedures, personnel training, and functional performance of the HVAC systems are also critical for the success of a shelter-in-place building.

Testing the air tightness of such buildings can provide insight to more than just the quantitative results of air change rates or leakage areas of the buildings. This testing has logistical issues that can require interaction with site safety personnel, interaction with the building occupants including operations personnel, and the shutting down of HVAC equipment, all of which may provide an opportunity for the test engineer to gain a deeper understanding into how successful the buildings shelter-in-place strategy might be. BakerRisk has recently conducted air tightness testing at roughly 50 shelter-in-place buildings at chemical facilities. This testing has consisted of tracer gas tests, blower door tests, and infrared thermography. Additionally, BakerRisk has used methods such as visual inspections, building design review, review of procedure documentation, shelter-in-place drills, and formal and informal interviews with site safety personnel, operations personnel, building occupants, and HVAC technicians to better assess the suitability of a shelter-in-place buildings.

The quantitative testing and these more qualitative methods have provided insight into shelter-in-place procedures, personnel training, building design and building envelopes, HVAC systems, maintenance procedures, expedient sheltering, and locating major leaks. Many of these insights can be problematic, while other insights can be enlightening. This presentation will discuss a variety of observations regarding these subjects relating to sheltering-in place. While buildings can be tested to quantify how air tight they are, there are many other things to consider when assessing if shelter-in-place building is suitable, or if a shelter-in-place strategy will be successful. Several methods can be employed to gain insights into this assessment, some of which may have a greater impact on the risk that the test results themselves.