Residential Fire Safety SYSTEMS Sprinkler FITTINGS Comparison sheet
Sprinkler Fittings Flow Comparison: Expansion vs. Insert Differences in PEX
PEX-based multipurpose residential fire sprinkler systems use either expansion fittings or insert fittings. This comparison sheet shows the differences in flow rates between the two fittings, and the resulting impact on system design and cost.
There are three different types of PEX: PEX-a, PEX-b and PEX-c. Uponor manufactures PEX-a tubing, which has a shape memory that allows expansion of the tubing to insert a larger-diameter fitting. The tubing then naturally and quickly shrinks back down around the fitting, forming a strong, reliable, high-flow connection.
B
B
B - Internal diameter
6
5 8
3
4
5
A 3x R .02
D
2. Additional tubing and fittings to provide an acceptable flow and pressure to each sprinkler 3. More sprinklers, spaced closer together, to reduce system pressure requirements
3
2
.60 REF.
Performance Comparison: ProPEX Expansion vs. Insert
R .438 3x P1110502-AA
1. A booster pump to provide acceptable system pressure
ASTM F1807 Insert Fitting
2
6
7
Compared to Uponor’s expansion fitting system, a system using insert fittings will likely require one or more of the following.
PEX-b tubing does not have the same shape memory as PEX-a, so it requires insertion of a smallerdiameter fitting into the tubing. The tubing is then crimped or pressed onto the fitting.
A - Flow path
ASTM F1960 4 ProPEX® Expansion Fitting
The smaller-diameter fittings required with PEX-b tubing result in greater friction loss when performing water flow calculations. This increase in friction loss (measured in additional “feet of equivalent pipe”) reduces the water pressure available to the sprinklers.
6x 30?
+ .060 - .010
ÿ .60
D
"Date Code"
2.3 REF
D The table below shows the dimensional and performance differences between .60 Uponor’s ProPEX PEX-a expansion fittings and PEX-b insert fittings.
1/2"
6x .200
"Supplier ID"
±.020
"Country + .06 of Origin" - .01
ÿ .485 2x R.050
Criteria
Uponor ProPEX PEX-a Expansion
PEX-b Insert
Uponor Advantage
0.50 sq. in.
0.40 sq. in.
25% greater area
0.80"
0.71"
12% larger diameter
12.4 gpm
9.9 gpm
25% greater flow
9 feet
Superior hydraulic performance
8 feet
Superior hydraulic performance
3x .04
SECTION B-B
A
C
±.010
BACK SIDE MARKINGS DETAIL
Flow Area (Dimension A, 1" fitting)C Markings Detail
Internal Diameter (Dimension B, 1" fitting) MARKING BOARD TEXT EXTEND .008 REF.
Flow Rate (at 8 ft./sec.)
C
6x 30?
Equivalent Length (¾" branch tee)
3 feet
AI
B
.68 REF.
B
B
Equivalent Length (¾" elbow) .32 REF.
1.01 REF.
.24 REF.
REVISIONS ECO # DETAIL DATE BOTH NO PRINT SIDES MARKINGS
LETTER
SECTION A-A
A REVISIONS
UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES
AA CAD GENERATED DRAWING, DO NOT MANUALLY UPDATE
UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES TOLERANCES ARE: .X ± .06 .XX ± .01 .XXX ± .005 ANGLES ±1? SURFACE FINISH UNLESS OTHERWISE SPECIFIED:
WIRSBO COMPANY 09/06/06
AB
APV20650 08/10/05
AC
APV20718
3 feet .42 REF.
CAD GENERATED DRAWING, DO NOT MANUALLY UPDATE
DO NOT SCALE DRAWING THE INFORMATION CONTAINED IN THIS DRAWING IS THE SOLE PROPERTY OF UPONOR WIRSBO. ANY REPRODUCTION IN PART OR WHOLE WITHOUT THE WRITTEN PERMISSION OF UPONOR WIRSBO IS PROHIBITED.
WIRSBO COMPANY
5925 148TH STREET WEST APPLE VALLEY, MN 55124 PHONE (952) 891 - 2000 FAX (952) 891 - 1246
A
Sprinkler Design Layouts: ProPEX Expansion vs. Insert The following sprinkler designs illustrate the practical benefits of Uponor ProPEX PEX-a expansion fittings compared to PEX-b insert fittings for the same house.
ProPEX Expansion Design Layout
Insert Fitting Design Layout
Because of the high-flow expansion fittings, Uponor’s design uses only 391 feet of ¾" PEX-a tubing to generate 26 gallons of flow per minute to the sprinklers. Using Uponor large-diameter fittings in this design requires just 53.8 psi (using PEX-b lower-flow insert fittings would demand 83.2 psi, which would exceed safe working pressures for the system).
To overcome the flow restrictions and friction losses from smaller-diameter insert fittings, this design requires 628 feet of ¾" tubing to create a system that is able to operate at an acceptable 46.6 psi. (Using Uponor’s higher-flow expansion fittings on the same design would require only 37.5 psi.) Note that pressures in many jurisdictions are as low as 40 psi, so in this case, the system would require the installation of a booster pump.
Criteria Feet of tubing
FS_SprinklerCompareFS052_0311, Copyright © 2011 Uponor. Printed in the United States
Required pressure
Uponor ProPEX PEX-a Expansion
PEX-b Insert
391
628
35% lower psi
24% higher psi
Dry-fit Concerns
Conclusion
Since fire sprinkler systems using insert fittings can be pre-assembled by inserting the fitting without expanding the tubing (called dry-fitting), the installer has to remember to crimp or press the tubing onto every fitting. If the installer misses just one connection, expensive leaks can result. It is impossible to dry fit Uponor’s ProPEX expansion connections since the tubing has to be expanded before inserting the fitting.
The higher flow rate of Uponor’s larger-diameter ProPEX expansion fittings results in a more efficient system that requires fewer materials and less labor to install. • Less tubing (38% less in this example) • Fewer fittings and connections • Less labor to install •Lower pressure requirements (20% to 35% lower in this example) • No need for a pressure-increasing booster pump • Fewer sprinklers, spaced further apart • No potential for dry-fitting leaks
Uponor, Inc. 5925 148th Street West Apple Valley, MN 55124 USA Tel: 800.321.4739 Fax: 952.891.2008 Web: www.uponor-usa.com
Uponor Ltd. 2000 Argentia Rd., Plaza 1, Ste. 200 Mississauga, ON L5N 1W1 CANADA Tel: 888.994.7726 Fax: 800.638.9517 Web: www.uponor.ca