Brochure

Gastite Division, Titeflex Corporation
1116 Vaughn Parkway / Portland, TN 37148
800.662.0208 / www.gastite.com / [e-mail]
38
April 2015
Section 3: System Configuration
3.2.11 Example 10 - Commercial Elevated Pressure Series System – 2 PSI
Figure 3-18 below shows a typical commercial rooftop installation with four (4) appliances. e piping is arranged in series
with a main run branching at the appliances. e utility company’s supply pressure (downstream of the meter) is 2 PSI. e
utility company advises that the specific gravity of the gas delivered will be 0.60 and the energy content is 1 CFH = 1000
BTUH. e 2 PSI line pressure chart with a pressure drop of 1 PSI can be used. is will supply the regulators with the 1
PSI inlet pressure required for full capacity flow.
Table 3-11
Section Description Load Delivered by Section Section Length Run Length Tube Size
“A” – Trunk 1250 CFH = 1,250,000 BTUH 15 feet 60 feet 1-1/4" CSST
“B” – Trunk 1000 CFH = 1,000,000 BTUH 15 feet 60 feet 1" CSST
“C” – Trunk 750 CFH = 750,000 BTUH 15 feet 60 feet 1" CSST
“D” – Air Handler 500 CFH = 500,000 BTUH 15 feet 60 feet 3/4" CSST
“E” – Make-Up Air Unit 250 CFH = 250,000 BTUH 10 feet 25 feet 1/2" CSST
“F” – Make-Up Air Unit 250 CFH = 250,000 BTUH 10 feet 55 feet 1/2" CSST
“G” – Make-Up Air Unit 250 CFH = 250,000 BTUH 10 feet 40 feet 1/2" CSST
Run Length for Trunk Sections = Distance from meter to furthest appliance (Longest Run)
Run Length for Appliance Sections = Distance from meter to each appliance
SIZING RUN “A”
• Run “A” is sized by the total load of all appliances and the run length from the meter to the furthest appliance
• e total load of all appliances is 250 + 250 + 250 + 500 = 1250CFH
• e run length to the Air Handler (furthest appliance) is 15 + 15 + 15 + 15 = 60ft
• Referring to Table 7-10 (2 PSI line pressure, 1 PSI pressure drop): for a 60ft run, 1-1/4" CSST has a capacity over 1250CFH
(actual: 1854)
Fig. 3-18