December 18, 2025
From the 2024 UPC Illustrated Training Manual, Chapter 3, GENERAL REGULATIONS
313.5 Underground Installation. Piping in the ground shall be laid on a firm bed for its entire length; where other support is otherwise provided, it shall be approved in accordance with Section 301.2.
Care should be taken with underground piping to ensure that it is supported along its entire length. This is especially critical with underground drainage piping. There should be no sagging of the pipe. This will cause the drainage pipe to lose its grade and increase the possibility of blockage occurring in the installation. This is especially important with flexible piping such as plastic pipe materials (see Figure 313.5).
From the 2024 UMC Illustrated Training Manual, Chapter 9, INSTALLATION OF SPECIFIC APPLIANCES
925.5 Installation in Commercial Garages and Aircraft Hangars. Overhead heaters installed in garages for more than three motor vehicles or in aircraft hangars shall be listed and shall be installed in accordance with Section 303.11 and Section 303.12. [NFPA 54:10.16.5]
Suspended heaters of this type are required to be installed in a fixed position independent of the gas and electric supply lines. No combustible material is allowed for hangers or supports, and heaters subject to vibration shall be protected with isolating hangers.
Installations for listed and unlisted heaters shall comply with the proper clearances to combustibles and combustion and ventilation air requirements as discussed in this section.
NFPA 409 Standard on Aircraft Hangars, Section 7.13.5 also requires listed heaters for suspended or elevated heaters in aircraft hangars.
(This is not to be considered the official position of IAPMO, nor is it an official interpretation of the Codes.)
IAPMO
IAPMO develops and publishes the Uniform Plumbing Code®,the most widely recognized code of practice used by the plumbing industry worldwide; Uniform Mechanical Code®; Uniform Swimming Pool, Spa and Hot Tub Code®; and Uniform Solar Energy, Hydronics and Geothermal Code™ — the only plumbing, mechanical, solar energy and swimming pool codes designated by ANSI as American National Standards — and the Water Efficiency Standard (WE-Stand)™. IAPMO works with government, contractors, labor force, and manufacturers to produce product standards, technical manuals, personnel certification/educational programs and additional resources in order to meet the ever-evolving demands of the industry in protecting public health and safety.
Last modified: December 18, 2025