The house drainage system shall be so designed that there will be an adequate circulation of air in all pipes and no danger of siphonage, aspiration or forcing of trap seals under conditions of ordinary use.
Structure Delaware Code
Chapter 79. BASIC PLUMBING PRINCIPLES
§ 7902. Principles applicable throughout State.
§ 7903. Plumbing Code; adoption and enforcement.
§ 7905. Additional regulations.
§ 7907. Inspection and inspectors.
§ 7910. Cross connections with unsafe water supplies.
§ 7911. Adequate water supply.
§ 7913. Hot water tanks or boilers.
§ 7914. Separate sewer connections.
§ 7915. Family private water closet in multiple dwellings.
§ 7916. Plumbing fixture materials.
§ 7917. House drainage system.
§ 7919. Cleanouts in drainage systems.
§ 7921. Adequate air circulation.
§ 7922. Roof terminals, soil or waste stacks.
§ 7923. Water or air pressure test.
§ 7924. Substances entering house drainage system.
§ 7925. Connections with refrigerators.
§ 7926. Light and ventilation.
§ 7927. Private sewage treatment and disposal system.