Spacing Between Supports by "Design of Piping Systems, The M. W. Kellogg Company"
 
  Calculation as per Ecuations in Figures C-16 & C-17   
                         
  (Enter values in yellow cells for calculations)
  INPUT DATA
                         
  Pipe weight per m , W =    Kg/m     Diameter Nominal, DN = 
   
                         
  Weight of water per m, W =    Kg/m     Schedule  = 
   
                         
  Weight of pipe insulation per m, W =    Kg/m Outside Diameter =  mm  
                         
   Section module , Z =    mm³ Design Temp. =  ᵒC  
                         
  Moment of inertia, I =    mm⁴ Material Group =
   
        See ASME Sec. II D Table TM-1      
  Modulus of Elasticity, E =    N/mm² Insulation Thickness  = 
 mm  
  As per ASME Sec. II D Table TM-1                      
  Allowable longitudinal bending stress, S =    N/mm² (MPa) Insulation Density, ρ =   Kg/m³  
  As per table 121.5 on ASME B31.1                      
  Maximum Deflection, & =   mm The spacing is based on a fixed beam support    
  As per table 121.5 on ASME B31.1     with a bending stress not exceeding 15.86 MPa    
        and insulated pipe filled with water, and the pitch    
        of the line is such that a sag of 2.5 mm between    
        supports is permissible.    
        (As per table 121.5 on ASME B31.1).    
                         
                         
  CALCULATIONS
                         
  Pipe segment, L  =    m L = ( SZ ) ½        
  From Eq. S = 1.2WL/Z     981W          
                         
  Deflection, &  =     mm & = 98x10⁶WL⁴            
  Maximum Deflection 2.5 mm     EI            
  Satisfies S and & =                       
                         
  Pipe segment, L  =    m L = ( &EI ) ¼        
  From Eq. & = 17.1WL^4/EI with &=2.5 mm     98x10⁶W          
  The spacing between supports    m                  
                         
                       
  Spacing Between Supports by "Design of Piping Systems, The M. W. Kellogg Company"
 
  Calculation as per Ecuations in Figures C-16 & C-17   
                         
  (Enter values in yellow cells for calculations)
  INPUT DATA
                         
  Pipe weight per m , W =    lb/ft Nominal Pipe Size, NPS = 
   
                         
  Weight of water per m, W =    lb/ft     Schedule  = 
   
                         
  Weight of pipe insulation per m, W =    lb/ft Outside Diameter =  in  
                         
   Section module , Z =    in³ Design Temp. =  ᵒF  
                         
  Moment of inertia, I =    in⁴ Material Group =
   
        See ASME Sec. II D Table TM-1      
  Modulus of Elasticity, E =    psi Insulation Thickness  = 
 in  
  As per ASME Sec. II D Table TM-1                      
  Allowable longitudinal bending stress, S =    psi Insulation Density, ρ =   lb/ft³  
  As per table 121.5 on ASME B31.1                      
  Maximum Deflection, & =   in The spacing is based on a fixed beam support    
  As per table 121.5 on ASME B31.1     with a bending stress not exceeding 2,300 psi    
        and insulated pipe filled with water, and the pitch    
        of the line is such that a sag of 0.1 in. between    
        supports is permissible.    
        (As per table 121.5 on ASME B31.1).    
                         
                         
  CALCULATIONS
                         
  Pipe segment, L  =     ft L = ( SZ ) ½        
  From Eq. S = 1.2WL/Z     1.2W          
                         
  Deflection, &  =      in & = 17.1WL⁴            
  Maximum Deflection 0.1 in.     EI          
  Satisfies S and & =                       
                         
  Pipe segment, L  =     ft L = ( &EI ) ¼        
  From Eq. & = 17.1WL^4/EI with &=0.1 in.     17.1W          
  The spacing between supports     ft                  
                         
                               
    Discussion and References
      Information about Spacing Between Support
      Design of Piping Systems, The M. W. Kellogg Company
    Books & Tables
  - Design of Piping Systems, The M. W. Kellogg Company    
  - Pipe Properties
  - Insulation Weight Factor
  - Insulation Density
  - ASME Sec. II D Table TM-1 ( Modulus of Elasticity,  E )
    Spacing vs. Stress                      
    (The spacing is based on a fixed beam support with a bending stress not exceeding 2,300 psi as per table 121.5 of ASME B31.1).  
    In most cases an estimate of the stress can be obtained from the equation for beams:    
(U.S. Customary Units) 
    & = 1.2WL²    
L = ( SZ ) ½   (From Fig. C-16, Design of Piping Systems, The M. W. Kellogg Company,  
    Z     1.2W     Published by Stellar Editions, 2016).  
                               
    (SI Units)                         
    & = 981WL²    
L = ( SZ ) ½        
    Z     981W          
                               
Where:
    S = maximum bending stress, psi (Mpa)  
    W = total unit weight, lb/ft (Kg/m)  
    L = pipe segment, ft (m)  
    Z = section modulus, in³ (mm³)  
    For larger concentrated loads, such as those produced by valves, vertical sections, branches, etc., Supports must be  
placed as close as possible.
The effect of concentrated loads (valves, etc.) not located in the supports must be approximated by multiplying the
    stress by 2P/WL, where “P" is the concentrated load in pounds.  
                               
    Spacing vs. Deflection                  
    (Pipe deflection could be limited to 0.1 in. as per table 121.5 of ASME B31.1)    
    The deflection of a section can be approximated by the following formula:    
    (U.S. Customary Units)                       
    & = 17.1WL⁴    
L = ( &EI ) ¼   (From Fig. C-17, Design of Piping Systems, The M. W. Kellogg Company,  
    EI     17.1W     Published by Stellar Editions, 2016).  
                               
    (SI Units)                         
    & = 98x10⁶WL⁴    
L = ( &EI ) ¼        
    EI     98x10⁶W          
                               
    Where:                        
    & = Deflection, in. (mm)  
    W = total unit weight, lb/ft (Kg/m)  
    L = pipe segment, ft (m)  
    E = modulus of elasticity, psi (N/mm²)  
    I = moment of inertia, in⁴ (mm⁴)