This provision is a subjective immission control with a curfew. A propane cannon is used to keep animals and birds from destroying commercial crops. In large fields, many are used and fired as frequent intervals. The sound levels are equivalent to the firing of a small artillery cannon. The provision may contain requirements that limit the number of cannons permitted in a specific area and the number firings per hour for each cannon. Many US states have a Right to Farm Act that limits nuisance litigation. Florida stated that it was a purpose of their act to protect reasonable agricultural activities conducted on farm land from nuisance suits. They also added a section that limited expand of operations without consideration of noise. Fairfax County, VA (Sections 105-4-4 and 108-5-1) require agricultural operation to meet maximum land use regulations and prohibit unnecessary noise. British Columbia Ministry of Agriculture (Farm Nuisance Noise document) have developed a comprehensive set of rules for cannon use.