API RP 500

NSTALLATIONS  AT PETROLEUM RECOMMENDED PRACTICE FOR CLASSIFICATION OF LOCATIONS FOR ELECTRICAL INSTALLATIONS AT F ACILITIES CLASSIFIED  AS CLASS I, DIVISION 1  AND DIVISION 2

61

Sample valve, bleed valve, or  similar device

0.5 m (18 in.)

0.5 m (18 in.)

0.5 m (18 in.) 1 m (3 ft ) Gas operated surface safety valve actuator vent port

Division 1

Division 2

Figure 39—Flowing Well in a Nonenclosed Adequately Ventilated Area and Without a Cellar or Below Grade Sump (See 10.5.1.1 and 10.15.3.2)

0.5 m (18 in.)

Sample valve, bleed valve, or  similar device

0.5 m (18 in.) 0.5 m (18 in.) 0.5 m (18 in.) Grade 3 m (10 ft)

3 m (10 ft)

Cellar 

Division 1

Division 2

Figure 40—Flowing Well in a Nonenclosed Adequately Ventilated Area With an Inadequately Ventilated Cellar or Below Grade Sump (See 10.5.1.2 and 10.15.3.2)

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