AnsweredAssumed Answered

NFPA 820 Table 4.2.2

Question asked by kyle.lynch on Oct 26, 2017
Latest reply on Oct 27, 2017 by kristhorsteinsson

Row 16 of Table 4.2.2 of NFPA-820-2016 indicates the NEC Area Electrical Classification of the wet wells will be Division 1 or Division 2, based on the mechanical ventilation (A or B as per noted by this Table) to be provided. In both of the cases, the CGD is required as of the means of Fire Protection Measures.

 

Row 17 of the table indicates the NEC Area Electrical Classification of the drywells will be Unclassified or Division 2, based on the mechanical ventilation (C or D as per noted by this Table) to be provided. To either of the cases, no CGD is required to the means of Fire Protection Measures.

 

 

Can please clarify the reasons why the CGD is not required to the cases as per Row 17, especially when there is no ventilation or ventilated at less than six air changes per hour and the area’s classification remains as Division 2?  

 

Thank you.

Outcomes