Can poisonous Carbon Monoxide diffuse through building walls?

Fire Protection Research Foundation report: "Carbon Monoxide Diffusion through Porous Walls: A Critical Review of Literature and Incidents". Authors: Izabella Vermesi, Francesco Restuccia, Carlos Walker-Ravena and Guillermo Rein, Imperial College London
 
  It has been reported recently that in laboratory conditions carbon monoxide (CO) diffuses through gypsum board at a surprisingly high rate (Hampson, et al., JAMA 2013). Because CO is poisonous and a by-product of systems typically present in residential housing like boilers, generators, furnaces and automobile engines, this finding could have a significant impact on the life safety standards published by National Fire Protection Association (NFPA) and International Code Council (ICC), such as NFPA 101 Live Safety Code. For example, in USA, state legislation mandates the requirements for CO detection and warning equipment to be installed, but currently only enforces CO detection if there are communicating openings between the garage and occupied areas of a building.

Comparison between the experimental results for 0.5" gypsum wallboard

With the sponsorship of the Fire Protection Research Foundation, we have conducted a literature review on CO diffusion through walls that can be read here (open access). We have analyzed in detail the data from the recent experiments with a mass transfer model and confirm the validity of the findings for gypsum board. We have also found a number of actual incidents and laboratory experiments which confirmed the transport of CO through other types of porous walls. We also found studies on the transport of other hydrocarbon gases with larger molecules than CO that can also diffuse through porous walls.

Our analysis and review independently confirms that CO can diffuse through porous walls at a fast rate and that the phenomena may merit consideration in life safety standards.