The length caculation for thermal screen(curtain) when purchase
We suggest that using the following formula to caculate how length the thermal screen you need to purchase:
Purchase length=greenhouse theoretical length+greenhouse theoretical length x theoretical shrinkage rate(0.5%)+greenhouse theoretical length x curtain weight of prolapse rate(1%) + the length of extra curtain on the two side x 2.
For example: If the greenhouse theoretical length is 70 meters, you can use the above formula to cacutale out the curtain length you need to purchase for 1 roll.
70+70*0.005+70*0.01+0.6*2=72.25meters.
Remark:
1. The length of greenhouse means the theoretical length when design greenhouse in the beginning.
2. The theoretical shrinkage rate: we give shrinkage rate less than 2% within 5 years produced by us, but it will be no more than 0.5% in the beginning of installation, so if the greenhouse is 70meters, the curtain theoretical shrinkage length should be 70 x 0.005meter.
3. The weight of prolapes of curtain: according to installation quality, usually 1% should be considered.
4. The length of extral curtain on the two side after installation: mainly to insure the seal is tight enough for supporting(hanging) system and uniformation on the two side of curtain after installation. we suggest giving the length of extral curtain on the two side as per the following datas.
If greenhouse is 10-50 meters, extral curtain for every side should be 0.6 meter.
If greenhouse is 50-100 meters, the extral curtain for every side should be 1.2 meter.
if greenhouse is more than 100 meters, th extral curtain for every side should be 1.3meter.