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25 Cards in this Set
- Front
- Back
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The volume of dry gas varies inversely with the absolute pressure when the temperature remains constant? |
Boyle's law V¹P¹=V²P² |
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The volume of gas varies directly with temperature provided that the gas pressure remains constant? |
Charles law II T¹ / T²=P¹ / P² |
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The pressure of gas varies directly with temperature provided that the volume of the gas remains constant? |
Charles law I P¹ / P² = T¹ / T² |
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Which of the gas meters listed is a positive displacement meter? A. Orifice meter B. Turbine meter C. Rotary meter D. Venturi tube meter |
Rotary meter |
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Which orifice type is used to measure flow rate rather than control a flow rate? |
Orifice plate |
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Which type of orifice is the most common and least expensive? |
Fixed oriface |
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What four factors determine the flow through an orifice? |
K-factor, specific gravity, area and pressure drop. |
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Which angle of approach will provide the greatest flow through a fixed orifice? |
15% |
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Which factor has the greatest effect on the flow rate through an orifice? |
Area |
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If a gas fitter clock the gas meter supplying an appliance and found that the input was only half the required input, what would he do to solve the problem? |
Double the area of the orifice |
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All gas piping must be tested before the installation can be considered complete and in service, which tests will be performed before attempting light up? |
Piping pressure test and meter dial test |
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You are to conduct a pressure test on 65 ft of 1.25" black iron pipe the most economical method of pressurizing the piping is? |
Tire pump |
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You are to pressure test 200' of 6" steel underground gas piping the most economical method of pressurizing the piping is? |
Nitrogen bottles |
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List the code requirements concerning test pressure gauges? |
Dial to exceed test pressure by 15 to 300% |
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What is the minimum test pressure as per code requirements of 176 feet of 5 inch nominal pipe sizing schedule 40 steel pipe installed underground operating at a pressure of 40 PSIG? |
50 PSIG |
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Purging using an inert gas is a requirement on 4" diameter pipe but not on smaller piping why? |
Larger piping cannot withstand an explosion from a gas air mixture |
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What is The Purge velocity required in a piping system? |
200' per minute |
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What is The Purge Point velocity required to be in the piping system |
200' per second |
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What is the equation for calculating the diameter of required Purge point? |
square root - D² / 60 |
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Where are the test pressures for piping systems located in the BC149. 1 code book? |
Table 6.3 |
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Find volume of piping |
V=(D² x . 7854) x L Always convert from inches to feet. Exp. (6"/12")² =. 5' |
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Find number of NO² cylinders required? |
Volume of pipe/225.5 ft³ NO² |
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Find diameter of purge opening? |
^d²/60^ = square root |
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Find time of purge? |
Feet of pipe/200' min x 2(saftey factor) |
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Pressure left in cylinders? |
P²=P¹ x V¹/ V² P¹=14.73 (atmospheric pressure) V¹=225.5 (NO²) - volume of pipe P²=? V²=volume of cylinder |
