D.C. Mun. Regs. tit. 21, r. 21-1824
The American Society for Testing and Materials (ASTM) standard A-120/A-53 steel shall be used for subsurface freeze pipes, unless otherwise approved in a well construction work plan by the Department in accordance with §§ 1803.10 and 1803.11.
The subsurface connections of steel freeze pipes installed in a ground freeze well shall be welded.
A ground freeze well system shall be installed by a licensed well driller experienced in installing ground freeze well systems or trained, certified, or accredited by a recognized professional organization specializing in the installation of ground freeze well systems.
Flushing, purging, pressure, and flow testing of a ground freeze well and system components shall meet the following requirements:
No coolant fluid or refrigerant circulated within the ground freeze downhole piping or ground freeze distribution manifold shall contain any substances that pose a hazard to public health and safety or the environment.
Pressure testing of the ground freeze well system shall be conducted and operating pressures shall be maintained in accordance with the manufacturer's specifications prior to putting the system into operation.
D.C. Mun. Regs. tit. 21, r. 21-1824