Case Studies Frame
Our commercial frames are manufactured from ZN35 high tensile structural steel, weld repaired tubing, (weld repair being of molten zinc) 44.45mm and 50.80mm diameter.
This is pre-galvanised inside and out, to provide a corrosion-free structure for many years. This means our steel tubing is almost twice as strong when compared to standard steel tube.
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Its’ minimum typical mechanical values against normal materials (in brackets) are as follows:
ZN35 Minimum yield strength 350 N/mm2 (Normal steel Minimum 200N/mm2)
ZN35 Minimum Tensile strength 450 N/mm2 (Normal steel minimum 300N/mm2)
Keder Cladding
The layered laminate plastic material with it’s bespoke integrated cellular structure (bubbles) has been specifically developed to combine light transparency with good heat insulation, and is available in 2 metre widths, with a welded seal.
Keder cladding stabilises summer daytime temperatures as well as retaining heat overnight, whilst insulating properties assist with reducing condensation. The unique bubble design causes a considerable scattering of light up to 83%, 30% of which is healthy infrared light, diffusing through more than 100 air burls (bubbles) per square foot. The diffused light scatters evenly so as to avoid and eliminate the common difficulties of both shading and burning areas within the greenhouse, which ensures the promotion of healthy plant growth.
The layer of sealed air in the Keder sheeting provides a high level of insulation and heat retention. Cladding in Keder has been proven to give up to 50% reduction in heating costs when compared with traditional glasshouses.
How do we apply the Cladding to our structures?
The structures are designed on a 2 metre increment spacing for the steel frame. Our profile (which the Keder Cladding fits into) is then secured in place. Once the frame has been assembled and the profile is secured in position, the Keder Cladding is fed through the profile, tensioned and secured in place.
Strength & snow load test
Keder Cladding is versatile and strong. It withstands high winds and heavy snow fall.
Colin stood on an unsupported panel.
The Product was tested for snow load under real conditions in Amherst, NH in February 2012. The following conditions were applied:
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- Sheet of LP-Keder tested 2m x 2m
- LP-Keder-Lock-Profile (PVC) used on two sides of the trial stand
- Tongue and groove system with Cambia battens on the other two sides of the stand
- Snow weight was determined (5 US liquid gallons = 20.5 lbs.)
- Geometric shape applied for estimation of snow load: pyramid
(Calculation of weight of snow on Keder – as produced by CE, USA)
Calculation m²=p.v Si-System =m²=492kg/m³.4.47m³=2199.24kg = 4848.50lbs = 2.199 Tonne
Thermal measurements
To provide some technical data on Keder’s energy saving properties, in comparison with other materials on the market, we have set out below relevant information on the heat saving properties. If you need more information please contact us on:
01386 49094 or email sales@kedergreenhouse.co.uk
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R Value: The R Value is the resistance to the flow of heat, therefore the higher the R Value number the better it is.
R-value – Thermal Resistance. Thermal resistance is the temperature difference, at steady state, between two defined surfaces of a material or construction that induces a unit heat flow rate through a unit area.
U Value
The U Value is the measure of the rate of heat loss or gain through a material, and the greater the products resistance to the heat flow the better its insulating value.
Therefore the lower the U Value number the better it is.
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U-value – Thermal Conductance. Thermal conductance is the time rate of steady state heat flow through a unit area of a material or construction induced by a unit temperature difference between the body surfaces, in W/(m2.K).
U-value, hence, is the reciprocal of the R-value.
Thermal
Thermal resistance (R) and thermal conductance (U) of the materials are reciprocals of one another and can be derived from thermal conductivity (k) and the thickness of the materials.
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The U and R values in the brochure are based on not only the measurement of heat conductivity of the material itself, but on the fact that the material is applied on the greenhouse. The difference is the situation that additional R(se) and R(si) are added to the total R value which will then give a lower U value in return.
This is why the given k-value cannot directly be translated into U value by doing the calculation U=k/L K-value.
Thermal conductivity is the time rate of steady state heat flow through a unit area of a homogeneous material induced by a unit temperature gradient in a direction perpendicular to that unit area, W/(m.k).
Gutters, Doors and Timber
Quality gutter systems for commercial greenhouses
Our gutters are made from high quality pre-galvanised 2mm steel sheets, to provide long-lasting protection from rust, corrosion and weathering.
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The greenhouse guttering is fitted along both sides and in the valleys of the structure, where applicable, with down pipes to remove excess rainwater.
Commercial greenhouse sliding doors
All doors are top track sliding doors, which not only add effective security to your structure, but also add style and efficiency.
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Manufactured for a range of commercial greenhouse sizes and styles, our quality sliding doors can be quickly and easily opened for entry and exit.
Our complete range of greenhouse doors are manufactured from 40mm x 40mm box section steel and hot dip galvanised for additional strength. Door fixtures are also suitably plated to protect the material against corrosion and ensure minimum maintenance.
Ventilation
In any greenhouse, the ventilation system plays a vital role in plant health and crop production.
As standard, all of our Keder Greenhouse commercial builds include manual outer wall vents, which operate on a bob weight system, opening from top down.
This maintains optimum air circulation.
Greenhouse ventilation for optimum growing
The Keder Greenhouse side ventilation system operates via a manual gearbox and is designed to be simple, efficient and maintenance free.
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The vent operates on a bob weight system, dropping down from gutter level, providing a maximum opening of 1,300mm. This effectively enables airflow high up where it is needed most.
If your desired greenhouse is of a triple span or greater, a central roof vent system can also be incorporated into the higher bays, if required. (This is referred to as cathedral roof vent design system).
Should further ventilation be required, end vents can also be designed and incorporated.
Efficient ventilation systems
These greenhouse vents can be upgraded with the addition of electric thermostatic control units, which are designed to be simple in operation and use.
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Each unit operates independently, opening and closing a single vent, relative to your desired temperature.
The control of the unit it totally programmable to set response and delay times, as well as varying stages of opening and closing.