function selfVentSizing (form) {

//get information from form
var flow = form.flow.value
var pipeschd = form.pipesch.options[form.pipesch.selectedIndex].text
flow = parseFloat(flow)


var g = 32.2

var sch = new Array (4)
sch[0] = "SCH 40"
sch[1] = "SCH 80"
sch[2] = "SCH 160"
sch[3] = "Sanitary OD Tubing"

var pSize = new Array (18)
pSize[0] = 0.5
pSize[1] = 0.75
pSize[2] = 1
pSize[3] = 1.5
pSize[4] = 2
pSize[5] = 2.5
pSize[6] = 3
pSize[7] = 4
pSize[8] = 5
pSize[9] = 6
pSize[10] = 8
pSize[11] = 10
pSize[12] = 12
pSize[13] = 14
pSize[14] = 16
pSize[15] = 18
pSize[16] = 24
pSize[17] = 30

//Put in schedule size arrays for each schedule
 
var SCH40 = new Array (18)
SCH40[0] = 0.622
SCH40[1] = 0.824
SCH40[2] = 1.049
SCH40[3] = 1.61
SCH40[4] = 2.067
SCH40[5] = 2.469
SCH40[6] = 3.068
SCH40[7] = 4.026
SCH40[8] = 5.047 
SCH40[9] = 6.065
SCH40[10] = 7.981
SCH40[11] = 10.02
SCH40[12] = 11.938
SCH40[13] = 13.124
SCH40[14] = 15
SCH40[15] = 16.876
SCH40[16] = 22.624
SCH40[17] = "NA"

var SCH80 = new Array (18)
SCH80[0] = 0.546 
SCH80[1] = 0.742 
SCH80[2] = 0.957 
SCH80[3] = 1.5 
SCH80[4] = 1.939 
SCH80[5] = 2.323 
SCH80[6] = 2.9 
SCH80[7] = 3.826 
SCH80[8] = 4.813 
SCH80[9] = 5.761 
SCH80[10] = 7.625 
SCH80[11] = 9.562 
SCH80[12] = 11.374 
SCH80[13] = 12.5 
SCH80[14] = 14.312 
SCH80[15] = 16.124 
SCH80[16] = 21.562 
SCH80[17] = "NA"

var SCH160 = new Array (18)
SCH160[0] = 0.466 
SCH160[1] = 0.614 
SCH160[2] = 0.815 
SCH160[3] = 1.338 
SCH160[4] = 1.687 
SCH160[5] = 2.125 
SCH160[6] = 2.624 
SCH160[7] = 3.438 
SCH160[8] = 4.313 
SCH160[9] = 5.187 
SCH160[10] = 6.813 
SCH160[11] = 8.5 
SCH160[12] = 10.126 
SCH160[13] = 11.188 
SCH160[14] = 12.812 
SCH160[15] = 14.438 
SCH160[16] = 19.312 
SCH160[17] = "NA"

var SanitaryODTubing = new Array (18)
SanitaryODTubing[0] = 0.37
SanitaryODTubing[1] = 0.62
SanitaryODTubing[2] = 0.87
SanitaryODTubing[3] = 1.37
SanitaryODTubing[4] = 1.87
SanitaryODTubing[5] = 2.37
SanitaryODTubing[6] = 2.87
SanitaryODTubing[7] = 3.834
SanitaryODTubing[8] = "NA" 
SanitaryODTubing[9] = 5.782
SanitaryODTubing[10] = 7.782
SanitaryODTubing[11] = "NA"
SanitaryODTubing[12] = "NA"
SanitaryODTubing[13] = "NA" 
SanitaryODTubing[14] = "NA" 
SanitaryODTubing[15] = "NA"
SanitaryODTubing[16] = "NA"
SanitaryODTubing[17] = "NA"

//find minimum diameter of pipe needed
var minimumDiameterFt = Math.pow(((4*flow*0.002228)/(0.3*3.14*Math.pow(g,0.5))),0.4)
var minimumDiameterIn = minimumDiameterFt*12



//get pipe diameter in feet
var pipeDia

//Find actual pipe diameter by looking through pipe schedule arrays

if (pipeschd == "SCH 40"){
        for (var i = 0; i  <= pSize.length; i++){

 if (SCH40[0] > minimumDiameterIn) {
          pipeDia = pSize[0]
          break
          }         
              if (SCH40[i] > minimumDiameterIn) {
              pipeDia = pSize[i]
              break
              }
       }
}


if (pipeschd == "SCH 80"){
        for (var i = 0; i  <= pSize.length; i++){

          if (SCH80[0] > minimumDiameterIn) {
          pipeDia = pSize[0]
          break
          }

              if (SCH80[i] > minimumDiameterIn) {
              pipeDia = pSize[i]
              break
              }
       }
}


if (pipeschd == "SCH 160"){
        for (var i = 0; i  <= pSize.length; i++){

          if (SCH160[0] > minimumDiameterIn) {
          pipeDia = pSize[0]
          break
          }

              if (SCH160[i] > minimumDiameterIn) {
              pipeDia = pSize[i]
              break
              }
       }
}

if (pipeschd == "Sanitary OD Tubing"){
        for (var i = 0; i  <= pSize.length; i++){

          if (SanitaryODTubing[0] > minimumDiameterIn) {
          pipeDia = pSize[0]
          break
          }

              if (SanitaryODTubing[i] > minimumDiameterIn) {
              pipeDia = pSize[i]
              break
              }
       }
}


pipeDia = parseFloat(pipeDia)

minimumDiameterIn = minimumDiameterIn*100
minimumDiameterIn = Math.round(minimumDiameterIn)
minimumDiameterIn = minimumDiameterIn/100

form.sizing.value = pipeDia
form.sizing2.value = minimumDiameterIn

}