<!-- You need a Java Enabled Browser to use the Vent Calculator.
// COPYRIGHT © S.Westenskow 1997-2000 e-mail: XSSpl@hotmail.com ***
function minimumPort(){
		if (document.forms[0].elements[0].checked){sd=0.01407}
		else{
			if (document.forms[0].elements[1].checked){sd=0.0215}
		else{
			if (document.forms[0].elements[2].checked){sd=0.0330}
		else{
			if (document.forms[0].elements[3].checked){sd=0.0450}
		else{
			if (document.forms[0].elements[4].checked){sd=0.0855}
		else{
			if (document.forms[0].elements[5].checked){sd=0.126}
		else{sd=0}}}}}}
var diver = document.forms[0].elements[9].value/1000
var Vg  = sd * diver
var vA  = Vg * document.forms[0].elements[8].value
if (document.forms[0].elements[6].checked){mp = (39.37 * Math.pow(((document.forms[0].elements[10].value) * vA), 0.5))}
		else{
if (document.forms[0].elements[7].checked){mp = (39.37 * (Math.pow(((411.25 * vA)/(Math.sqrt((document.forms[0].elements[10].value/2)))), 0.5)))}
		else{mp=0}}
var Vd1  = mp
var Vda  = Vd1/2
var Vd2  = Math.PI * (Math.pow(Vda, 2))
valueVd1 = Math.round((Vd1)*100)/100
	document.forms[0].elements[11].value=valueVd1
valueVd2 = Math.round((Vd2)*100)/100
	document.forms[0].elements[12].value=valueVd2
var  Vd3 = Math.sqrt(Vd2)
valueVd4 = Math.round((Vd3)*100)/100
	document.forms[0].elements[13].value=valueVd4
}
function theOne (){
	var a = document.forms[1].elements[5].value * 1728
	var b = 1.463 * Math.pow(10, 7)
	var c = document.forms[1].elements[6].value
	var x = a/document.forms[1].elements[4].value
if (document.forms[1].elements[0].checked){ 	
	var d = document.forms[1].elements[7].value/2
      var e = Math.pow(d, 2)
	var f = b * e
	var g = (Math.pow (c, 2)) * x
	var h = (f/g)-(1.463 * d)
valueh = Math.round((h)*100)/100
	document.forms[1].elements[10].value=valueh
}
else {
	var sb = document.forms[1].elements[8].value
	var sc = document.forms[1].elements[9].value
if (document.forms[1].elements[1].checked && sb/sc>8){alert("You should use a height to width ratio less than 1\:8")}
if (document.forms[1].elements[1].checked && sc/sb>8){alert("You should use a width to height ratio less than 1\:8")}
	var i = sb * sc
	var j = i / Math.PI
	var k = Math.sqrt(j)
	var l = b * Math.pow(k, 2)
	var m = (Math.pow(c, 2)) * x
	var n = (l / m)-(1.463 * k)
if (document.forms[1].elements[3].checked && document.forms[1].elements[1].checked){n = n -(sc * 0.5)}
else {n=n}
valuen = Math.round((n)*100)/100
	document.forms[1].elements[10].value=valuen
}
}
// -->