Section 690-319 - Underground electrical installations(a) Housing.--Underground transformer stations, battery charging stations, substations, rectifiers and water pumps shall be housed in noncombustible structures or areas or be equipped with a fire suppression system. (1) When a noncombustible structure or area is used, these installations shall be: (i) ventilated with intake air that is coursed into a return air course or to the surface and that is not used to ventilate working places;(ii) ventilated with intake air that is monitored for carbon monoxide or smoke by an atmospheric monitoring system installed and operated according to 30 CFR 75.351 (relating to atmospheric monitoring systems). Monitoring of intake air ventilating battery charging stations shall be done with sensors not affected by hydrogen; or(iii) ventilated with intake air and equipped with sensors to monitor for heat and for carbon monoxide or smoke. Monitoring of intake air ventilating battery charging stations shall be done with sensors not affected by hydrogen. The sensors shall de-energize power to the installation, activate a visual and audible alarm located outside of and on the intake side of the enclosure and activate doors that will automatically close when either of the following occurs:(A) the temperature in the noncombustible structure reaches 165 degrees Fahrenheit; or(B) the carbon monoxide concentration reaches ten parts per million above the ambient level for the area or the optical density of smoke reaches .022 per meter. At least every 31 days, sensors installed to monitor for carbon monoxide shall be calibrated with a known concentration of carbon monoxide and air sufficient to activate the closing door, or each smoke sensor shall be tested to determine that it functions correctly.(2) When a fire suppression system is used, these installations shall be:(i) ventilated with intake air that is coursed into a return air course or to the surface and that is not used to ventilate working places; or(ii) ventilated with intake air that is monitored for carbon monoxide or smoke by an atmospheric monitoring system installed and operated according to 30 CFR 75.351. Monitoring of intake air ventilating battery charging stations shall be done with sensors not affected by hydrogen.(b) Applicability.--This section does not apply to: (1) Rectifiers and power centers with transformers that are either dry-type or contain nonflammable liquid if they are located at or near the section and are moved as the working section advances or retreats.(3) Permissible pumps and associated permissible switchgear.(4) Pumps located on or near the section and that are moved as the working section advances or retreats.(5) Small portable pumps.2008, July 7, P.L. 654, No. 55, §319, effective in 180 days [ 1/5/2009].