(a) All disinfection unit processes where chlorine is used as the disinfectant shall be provided with the following features for uninterrupted chlorine feed:

1. (1) Standby chlorine supply,
2. (2) Manifold systems to connect chlorine cylinders,
3. (3) Chlorine scales, and

4. (4) Automatic devices for switching to full chlorine cylinders.

   Automatic residual control of chlorine dosage, automatic measuring and recording of chlorine residual, and hydraulic performance studies may also be required.

(b) All disinfection unit processes where chlorine is used as the disinfectant shall be provided with one of the following reliability features:

1. (1) Alarm and standby chlorinator;
2. (2) Alarm, short-term retention or disposal provisions, and standby replacement equipment;
3. (3) Alarm and long-term storage or disposal provisions;
4. (4) Automatically actuated long-term storage or disposal provisions; or
5. (5) Alarm and multiple point chlorination, each with independent power source, separate chlorinator, and separate chlorine supply.