One of our most popular structures is the hanley tunnel because it is the cheapest way of covering an area for season extension.
As a way of addressing some of the challenges and limiting factors with the tunnels, we have come up with a modified hanley.
The two areas where it significantly improves on the regular tunnel are the side clearance and the peak for snow shedding. Instead of using 24’ of steel to make 17’ wide and 7’6” high, we are using 26’ of material to make 16’ wide and 9’ high. It still uses 28’ wide plastic with extra at the ends to make the same kind of “tails”.
Sliding the plastic up on the sides is still the way that the tunnel is ventilated and you will still have the same challenges as far as creating access.
The re-bar anchors, base plates, clasps and rope are the same on the modified hanley as they are for the regular tunnel. We supply 5’ more of extra plastic for the tails since the building is taller.
The peak on the end hoops are very hard on the plastic, so we have designed a more rounded hoop at each end. It is strongly recommended to have 3 guides ropes at each end to brace back to the anchoring posts of the plastic.
Any structure with ends is not considered a Hanley Tunnel. We are more than willing to discuss the differences and benefits/drawbacks between tunnels and cold frames should you wish to know more.
The main thing which is critical to understand before going with a modified hanley is the extra wind load which the structure will be subjected to. Going from 7’6” to 9’ high, results in a 40% increase in the wind load. This issue is what makes the correct tightness of the ropes an even more critical consideration.
It is also the reason why we strongly urge customers who
do not have any tunnel experience to start with a regular tunnel.