Blowoff valves constructed with integrally threaded bonnets shall not be permitted.
No blowoff pipe shall discharge directly into a sewer. When the blowoff discharge is to be ultimately led to a sewer, local plumbing codes shall be consulted concerning requirements for discharging products into sewers.
When a blowoff tank is used, it shall be designed and constructed in accordance with good engineering practice for the maximum pressure and temperature expected during the blowdown period with a factor of safety of at least 4. All blowoff tanks shall be provided with means for cleaning and inspection.
Cal. Code Regs. Tit. 8, § 764