Sewer gas Sewer gas Sewer gas is a complex mixture of toxic and nontoxic gases produced and collected in sewage systems by the decomposition of organic household or industrial wastes, typical components of sewage. Sewer gases may include hydrogen sulfide, ammonia, methane, esters, carbon monoxide, sulfur dioxide and nitrogen oxides. Improper disposal of petroleum products such as gasoline and mineral spirits contribute to sewer gas hazards. Sewer gases are of concern due to their odor, health effects, and potential for creating fire or explosions. Sewer gas is typically restricted from entering buildings through plumbing traps that create a water seal at potential
Damp (structural) likely to be functioning, as the materials from which damp proof courses are manufactured tend to have a long lifespan. However, it should be acknowledged that there are cases where existing damp proof courses fail for one reason or another. One indicator that is often used to determine if the source of dampness is rising damp (rather than other forms of dampness) is to look for the presence of salts – in particular a tell tale "salt band" or "tide mark" at the peak of the damp's rise. This is not a reliable method as salts and dampness can enter