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Spring Hanger Sizing

DETERMINING THE SIZE AND SERIES TO USE
The load to be carried in the operating condition and the installed to operating deflection must be accurately calculated by a stress engineer.  This data can be determined analytically by computer analysis or estimated by manual calculations.  To determine the optimum load to be carried by the spring hanger in the operating position, calculate the weight of the piping system in the " as installed condition" which is carried by a rigid support placed where the spring hanger is to be located.  The calculation should include 1.) the weight of the pipe, valves and fittings, 2.) the weight of the contents and insulation, and 3.) the weight of the hanger hardware below the spring hanger casing. Note:  For a Type G spring hanger, the load to be carried by the hanger should also include the catalog weight of the hanger unit itself.

Once the load to be carried is determined, the installed to operating deflection can be calculated by performing an operating case analysis with the optimum load considered as a constant acting upward force.  The analysis results will reflect the piping system deflection from the installed position to the operating position.

"EQUAL" spring hangers are designed and manufactured for the following ranges of movement:  1.25" (Fig. E-82), 2.5" (Fig, E-268), 5.0" (Fig. E-98), 7.5" (Fig. E-100) and 10” (Fig. E-110).  Knowing the ranges of movements accepted by "EQUAL" hangers, the operating load and the installed to operating deflection, you are now ready to select the spring that best fits your requirements.  Turn to the " Hanger Size and Series Chart" which can be found on page 21 (Imperial units), on page 22 (metric— kilograms/mm) and on page 23 (metric— Newtons/mm).  Moving from left to right between the upper and lower boundaries of the working range, find the first occurrence of your operating load.  If the movement from the installed position to the operating position is downwards, move upwards from the operating position on the chart by the amount of the movement to find the installed load.  If the movement from the installed position to the operating position is upwards, move downwards from the operating position on the chart by the amount of the movement to find the installed load.  In the event that the travel places you outside of the working range, you have the option to try using the next larger size spring or to move up to the next series of spring.  In other words, you can move from an E-82 to an E-268 spring or from an E-268 spring to an E-98 spring, etc.

Please note that the MSS Standard also states that the maximum load variation from the installed position to the operating position is 25%.  That means that the maximum movement for a Fig. E-82 spring hanger is approximately 3/4” (19 mm), for a Fig. E-268 spring hanger is approximately 1 1/2” (38 mm), for a Fig. E-98 spring hanger is approximately 3” (76 mm), for a Fig. E-100 spring hanger is approximately 4 1/2” (114 mm) and for a Fig. E-110 spring hanger is approximately 6” (152 mm).

Please note that for a variable spring hanger to be acceptable the operating load and the installed position must be within the working range on the chart.  If the load variation for the piping system application is found to not be acceptable using a variable spring hanger, then you should consider the use of a constant effort spring hanger. See pages 46-71 in this catalog for information about constant effort spring hangers.

ORDERING HANGER TYPE "A", "B", "C", “D” and "E" Specify:  Figure Number, Size, Type, Operating load, Installed position to Operating position Deflection including direction of movement, Customer's Tag Number, the Finish Desired and Travel Stops, if desired.

ORDERING HANGER TYPE "F" Specify:  Figure Number, Size, Type “F”, Operating load, Installed position to Operating position Deflection including direction of movement, Customer's Tag Number, the Finish Desired, Travel Stops, if desired, with “Load Flange”. The "Installed Height" should also be specified. Note that the installed height must be within the range defined in this catalog.

ORDERING HANGER TYPE "G" In addition to the information listed above for hanger types “A”, “B”, “C”, “D” & “E” specify the center to center rod dimension, the total load to be carried by the hanger assembly and the load to be carried by each spring hanger.

ORDERING OPTION:  In addition you may request any of the following: Preset Pieces, Travel Stops and Lifting Lugs.

EXAMPLE:  Fig. E-82 , Size 15 , Type C, Operating Load = 5400 Lbs., Installed Load = 3000 Lbs., Installed to Operating Movement = 0.25” down, TAG = SH-124BA, Finish = HDG, Travel Stops = Hydro. insert content here