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INDUSTRY, LABOR A HUMAN RELATIONS 43 Ind g The foregoing formula is Eased on Q=21,000 A 0.82 where Q=the amount of heat transferred. (f) [2-2.5.6] The total emergency relief venting capacity for any specific stable liquid can be determined by the following formula: Cubic feet of free air per hour= V = 1,337 V=cubic feet of free air per hour from Table 8.19-8. L = latent heat ul vaporization ,:f specific liquid in Btu per lb. M= molecular«e , ht of specific liquids. (g) [2-2.5.7.] For t.:nks containing stable liquids,the required air-flow rate of par. (d) or (f, may be mule, lied by the appropriate factor listed in the following schecule when protection is provided as indicated.Only one factor can be used for any one tank: .5 For drainage in accordance with sub. (4) (b) for tanks over 200 square feet of wetted area;or .3 For water spray in accordance with standards approved by the department, and drainage in accordance with sub. (4) (b);or .3 For insulation in accordance with subd. 1.;or .15 For water spray with insulation in accordance with subd. 1. and drainage in accordance with sub. (4) (b). 1.Insulation systems for which credit is taken shall meet the following performance criteria: a. Remain in place under fire exposure conditions, b. Withstand dislodgment when subjected to hose stream impinge- ment during fire exposure except that this requirement may be waived where use of solid hose streams is not contemplated or would not be practical,and c. Maintain a maximum conductance value of 4.0 Btu's per hour per square foot per degree F. (Btu/hr/sq ft/°F.) when the outer insulation jacket or cover is at a temperature of 1,660°F.and when the mean tem- perature of the insulation is 1,000°F. (h) [2-2.5.8] The outlet of all vents and vent drains on tanks equipped with emergency venting to permit pressures exceeding 2.5 psig shall be arranged to discharge in such a way as to prevent localized over- heating of or flame impingement on any part of the tank, in the event vapors from such vents are ignited. (i) [2-2.5.9] Each co tank venting device shall have stamped on it the opening pressure,the pressure at which the valve reaches the full open position and the flow capacity at the latter pressure.If the start to open pressure is less than 2.5 psig and the pressure at full open posi- tion is greater than 2.5 psig, the flow capacity at 2.5 psig shall also be stamped on the venting device.The flow capacity shall be expressed in cubic feet per hour of air at 60° F. and 14.7 psia. Register,March,1962,No.315