Hi:
Recent hail storms have massively destructed the vegetation in the tunnels farms in Pakistan.
Here are few suggestions for the future.
Problem:
1. PVC sheet is so thin to hold the pressure of fast moving hail and definitely cross it result in breakage.
2. We need something that can just prevent/tolerate the pressure of the hail. It can be one time cost.
3. You dont need to cover the whole tunnel, only 3-4 ft from center top each side will save the crop.
Options
The best and affordable solution:
Netting/hail netting
In picture no. 2: if you have this hail net about 1ft higher than the roof top of your tunnel, can well prevent crop from damage..
Italian research: A nice article
http://www.goodfruit.com/italians-study-light-shading/
Anti hail nets in Spain:
http://www.freshplaza.com/article/110625/Spain-Anti-hail-nets-to-palliate-subsidy-reductions
Check out the price on Alibaba.com for anti hail nets, its nothing compare to costly crop.
http://www.alibaba.com/product-detail/Anti-hail-net-systems-Hail-protection_1870921250.html
Now its upto us how we use it... we dont need to make a roof we need tilted angle to avoid accumulation of the hails,,,,
Alternate solutions:
1: For Temporary Tunnels (bamboo/metal rods and PVC sheet)
Fix two poles in the middle of the entrance on both sides, this pole should be about 1ft higher above top of Tunnel roof. Now, you should have light Tirpal or any material which is strong, roll on between two poles.This roll will be unrolled only when required otherwise it will remain on top rolled. Its just like top over top...
2: For both Temp. and permanent Tunnels Structures..
I think you all have seen the windows blinds used to prevent sunlight in the room. Just like that the flaps of about 1 ft width and length depends on your tunnel. Either it can be of metal or parachute cloth which is cheap. It should cover the 3-4 ft of the top from center each side and attached to lever which can be open and closed as required.
OR tilted to an angle to avoid accumulation of hails on cover
ref: http://www.hldqjx.com/
ref: http://www.curtain-line.com/Electric-shades/FCS.htm
Just for example, click this link to see it
http://www.alibaba.com/product-detail/FSS-Scroll-Roof-Blinds-roller-blinds_523886712.html
one set for 20sq meter is for $70 and I think you all can very well redesign it using local material or called REVERSE Engineering. rather than using poles of aluminium you can use metal strings and would be cheaper too, just like in many of the mosques they use metal strings to hold Tirpal to avoid sun light... These are just ideas and one has to use it according to their situation and availability of material.
Good luck
Hope it will serve the purpose. Feel free to ask if you have any query..
Recent hail storms have massively destructed the vegetation in the tunnels farms in Pakistan.
Here are few suggestions for the future.
Problem:
1. PVC sheet is so thin to hold the pressure of fast moving hail and definitely cross it result in breakage.
2. We need something that can just prevent/tolerate the pressure of the hail. It can be one time cost.
3. You dont need to cover the whole tunnel, only 3-4 ft from center top each side will save the crop.
Options
The best and affordable solution:
Netting/hail netting
To me the best option :
Pic: 1
pic: 2
http://www.geotex.co.za/home/index.php?ipkContentID=496 In picture no. 2: if you have this hail net about 1ft higher than the roof top of your tunnel, can well prevent crop from damage..
Italian research: A nice article
http://www.goodfruit.com/italians-study-light-shading/
Anti hail nets in Spain:
http://www.freshplaza.com/article/110625/Spain-Anti-hail-nets-to-palliate-subsidy-reductions
Check out the price on Alibaba.com for anti hail nets, its nothing compare to costly crop.
http://www.alibaba.com/product-detail/Anti-hail-net-systems-Hail-protection_1870921250.html
Now its upto us how we use it... we dont need to make a roof we need tilted angle to avoid accumulation of the hails,,,,
Alternate solutions:
1: For Temporary Tunnels (bamboo/metal rods and PVC sheet)
Fix two poles in the middle of the entrance on both sides, this pole should be about 1ft higher above top of Tunnel roof. Now, you should have light Tirpal or any material which is strong, roll on between two poles.This roll will be unrolled only when required otherwise it will remain on top rolled. Its just like top over top...
2: For both Temp. and permanent Tunnels Structures..
I think you all have seen the windows blinds used to prevent sunlight in the room. Just like that the flaps of about 1 ft width and length depends on your tunnel. Either it can be of metal or parachute cloth which is cheap. It should cover the 3-4 ft of the top from center each side and attached to lever which can be open and closed as required.
OR tilted to an angle to avoid accumulation of hails on cover
Just for example, click this link to see it
http://www.alibaba.com/product-detail/FSS-Scroll-Roof-Blinds-roller-blinds_523886712.html
one set for 20sq meter is for $70 and I think you all can very well redesign it using local material or called REVERSE Engineering. rather than using poles of aluminium you can use metal strings and would be cheaper too, just like in many of the mosques they use metal strings to hold Tirpal to avoid sun light... These are just ideas and one has to use it according to their situation and availability of material.
Good luck
Hope it will serve the purpose. Feel free to ask if you have any query..
Ibneadam
JURehman
Curiosity of nature will lead you to discovery and satisfaction. Jurehman
