Brochure

Gastite Division, Titeflex Corporation
1116 Vaughn Parkway / Portland, TN 37148
800.662.0208 / www.gastite.com / [e-mail]
31
April 2015
Section 3: System Configuration
3.2.8 Example 7 - Parallel System – 7"WC – Hybrid
Figure 3-15 below shows the same house and similar piping system as Example 2. e piping is arranged in parallel fashion,
with individual CSST appliance runs supplied by a main distribution manifold. e main trunk line (“A”) from the meter
to the distribution manifold is rigid pipe rather than CSST. e utility company’s supply pressure (downstream of the meter)
is 7"WC. 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 allowable pressure drop across the system has been determined to be 2"WC (supply pressure 7"WC - appliance
requirement 5"WC). 0.5"WC pressure drop will be taken over the rigid pipe trunk line and the remaining appliance runs.
Note: Rigid pipe sized using a 0.5"WC pressure drop table, as no 2.0"WC pressure drop table for Rigid pipe is available.
Table 3-8
Section Description Load Delivered by Section Section Length Run Length Tube Size
“A” – Rigid Trunk 221 CFH = 221,000 BTUH 45 feet 70feet 1" Rigid
“B” – Furnace 80 CFH = 80,000 BTUH 15 feet 60 feet 3/4" CSST
“C” – Water Heater 36 CFH = 36,000 BTUH 10 feet 55 feet 1/2" CSST
“D” – Range 52 CFH = 52,000 BTUH 20 feet 65 feet 1/2" CSST
“E” – Dryer/BBQ Trunk 53 CFH = 53,000 BTUH 20 feet 70 feet 1/2" CSST
“F” – Dryer 28 CFH = 28,000 BTUH 5 feet 70 feet 1/2" CSST
“G” – BBQ 25 CFH = 25,000 BTUH 5 feet 70 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 80 + 36 + 52 + 28 + 25 = 221CFH
• e run length to the BBQ (furthest appliance) is 45 + 20 + 5 = 70ft
• Referring to Table 7-23 (Rigid pipe 0.5"WC pressure drop): for a 70ft run, 1" pipe has a capacity over 221CFH (actual: 240)
SIZING RUN “B”
• Run “B” is sized by the load of the supplied appliance and the run length from the meter to the supplied appliance
• e load of the furnace is 80CFH
• e run length to the furnace is 45 + 15 = 60ft
• Referring to Table 7-4 (2.0"WC pressure drop) for a 60ft run, 3/4" CSST has a capacity over 80CFH (actual: 152)
Fig. 3-15