Compare us against the competition Commercial Experts in Structures Since 969. you grow Our polytunnels helpfaster! bigger, better & polytunnels raised beds cloches fruit cages 08 8730 npstructures.co.uk
About us At, we have been designing, manufacturing and constructing polytunnels for over 40 years. We now supply commercial polytunnels to some of the most prestigious polytunnel growers in the UK and Europe. It s all about being fit for purpose - the fixtures and fittings should be made of a commercial grade. You d never expect to find hobby polytunnel fittings on a commercial polytunnel... Our in-house team is a collaboration of mechanical engineers, structural engineers, architects and construction experts. Our services include carrying out studies and preparing application drawings* for planning permission and building regulation approvals. *Prior to an order this service will be subject to a standard charge which will be credited when an official order is received. What is a Commercial Polytunnel? Why have we made this comparison? The basic functions of a hobby polytunnel and a commercial polytunnel are exactly the same. They are both used to grow crops, whether it is fruit or flowers. The basic design of a hobby polytunnel and commercial polytunnel are therefore the same. A steel frame structure covered with polytunnel polythene. We ve made this comparison because we think it is important to highlight the differences between our structures and those of our competitors. We want to tell our customers the reasons we manufacture our polytunnels the way we do and show them the difference between the framework, fittings and polythene that we supply and those our competitors supply. The difference however, is scale. Commercial structures are wider and higher. they can also be combined to make very large, multispan structures. Because of their size commercial structures must be capable of withstanding the larger wind and snow loads imposed on them. This comparison looks at the Commercial Single Span polytunnels we supply and Commercial Single Spans polytunnels offered by our competitors. Notes from our Structural Engineer At, we have our own in-house team of design and construction engineers. John is our in-house Structural Engineer. He has gained Master & Bachelor of Engineering Degree in Architectural Engineering, awarded by The University of Leeds....We wouldn t, would you? We re all very proud of John and this achievements. and as he played a huge part of pulling together this comparison chart, we felt it only fitting he should have his own section. Throughout this brochure you will see blue stars on some of the comparison sections, such as anchor plates, hoop pieces and storm bars. These stars indicate there is note about these sections within our Structural Engineer notes. Notes from our Structural Engineer can be found on pages &. Look out for the blue stars! Turn to pages & for notes fro m our structural en gineer 3
8 ft Single Span Northern / 3.mm wall thickness to give increased Up to 0mm of tensioning is available by 0.8 mm High Tensile* 0.8 mm 0.8 mm 3 4 0.8 mm High Tensile* 0.8 mm High Tensile* 0.8 mm High Tensile* 3 mm High Tensile* Steel Size Tensioning System Hoop Diameter Number of Struts/Stabilizers per end. Strut/Stabilizer Bar Diameter Ridge Bar Diameter Main Crop Bar Diameter Number of Crop Bar Hangers Crop Bar Hanger Diameter End Timber Sizes Side Timber Sizes Base Rail Aluminium Section Sizes Side Rail Aluminium Section Sizes Type of Used 7 mm x 7 mm Tanalised 00 mm x 0 mm 00 mm x 0mm 00 mm x 0 mm Tanalised 7 mm x 47 mm 7 mm x 40 mm 70 mm x 0 mm 37 mm x 4 mm NO ALUMINIUM OPTION 70 mm x 0 mm mm x 4 mm NO ALUMINIUM OPTION Purpose made commercial fittings. U Bolts and/or Q Clips U Bolts / Q Clips / P Clips, Imported, Imported Gearbox operated 0 mm aluminium tube with Commercial Aluminium Door 7 mm x 0 mm Timber 7 mm x 0 mm Timber mm - Flexible LDPE Doors Every effort has been made to accurately represent the products of our competitors at the time of going to print. The findings above are based on information that is widely available on the internet. We suggest all customers research these finding before purchasing their own Commercial Polytunnel and not to base their decision on which supplier to select on the findings above.
ft Single Span Tensioning System Northern / 3.mm wall thickness to give increased Up to 0mm of tensioning is available by * Hoop Diameter 0.8 mm High Tensile** 0.8 mm 0.8 mm Number of Struts/Stabilizers per end. 7 Strut/Stabilizer Bar Diameter 0.8 mm High Tensile** Ridge Bar Diameter 0.8 mm High Tensile** Main Crop Bar Diameter 0.8 mm High Tensile** Crop Bar Hanger Diameter 3 mm High Tensile** * We have used the ft in this comparison as they do not offer a ft. * 6 Every effort has been made to accurately represent the products of our competitors at the time of going to print. The findings above are based on information that is widely available on the internet. We suggest all customers research these finding before purchasing their own Commercial Polytunnel and not to base their decision on which supplier to select on the findings above. Steel Size End Timber Sizes 7 mm x 7 mm Tanalised 00 mm x 0 mm 00 mm x 0mm Side Timber Sizes 00 mm x 0 mm Tanalised 7 mm x 47 mm 7 mm x 40 mm Base Rail Aluminium Section Sizes 70 mm x 0 mm 37 mm x 4 mm NO ALUMINIUM OPTION Side Rail Aluminium Section Sizes 70 mm x 0 mm mm x 4 mm NO ALUMINIUM OPTION Type of Used Purpose made commercial fittings. U Bolts and/or Q Clips U Bolts / Q Clips / P Clips Gearbox operated 0 mm aluminium tube with, Imported, Imported Doors Commercial Aluminium Door 7 mm x 0 mm Timber 7 mm x 0 mm Timber mm - Flexible LDPE Tensioning System Northern / 3.mm wall thickness to give increased Up to 0mm of tensioning is available by Hoop Diameter 60.3 mm High Tensile* 0.8 mm 0.8 mm Number of Struts/Stabilizers per end. 7 Strut/Stabilizer Bar Diameter 0.8 mm High Tensile* Ridge Bar Diameter 0.8 mm High Tensile* Main Crop Bar Diameter 0.8 mm High Tensile* Crop Bar Hanger Diameter 3 mm High Tensile* Steel Size End Timber Sizes 7 mm x 7 mm Tanalised 00 mm x 0 mm 00 mm x 0mm Side Timber Sizes 00 mm x 0 mm Tanalised 7 mm x 47 mm 7 mm x 40 mm Base Rail Aluminium Section Sizes 70 mm x 0 mm 37 mm x 4 mm NO ALUMINIUM OPTION Side Rail Aluminium Section Sizes 70 mm x 0 mm mm x 4 mm NO ALUMINIUM OPTION Type of Used Purpose made commercial fittings. U Bolts and/or Q Clips U Bolts / Q Clips / P Clips Gearbox operated 0 mm aluminium tube with, Imported, Imported Doors Commercial Aluminium Door 7 mm x 0 mm Timber 7 mm x 0 mm Timber Every effort has been made to accurately represent the products of our competitors at the time of going to print. The findings above are based on information that is widely available on the internet. We suggest all customers research these finding before purchasing their own Commercial Polytunnel and not to base their decision on which supplier to select on the findings above. 4 ft Single Span mm - Flexible LDPE 7
7 ft Single Span Tensioning System Northern / 3.mm wall thickness to give increased Up to 0mm of tensioning is available by Hoop Diameter 60.3 mm High Tensile* 60.3 mm 60.3 mm Number of Struts/Stabilizers per end. 7 6 7 Strut/Stabilizer Bar Diameter 0.8 mm High Tensile* 0.8 mm Ridge Bar Diameter 0.8 mm High Tensile* Main Crop Bar Diameter 0.8 mm High Tensile* 0.8 mm Crop Bar Hanger Diameter 3 mm High Tensile* 8 Every effort has been made to accurately represent the products of our competitors at the time of going to print. The findings above are based on information that is widely available on the internet. We suggest all customers research these finding before purchasing their own Commercial Polytunnel and not to base their decision on which supplier to select on the findings above. Steel Size End Timber Sizes 7 mm x 7 mm Tanalised 00 mm x 0 mm 00 mm x 0mm Side Timber Sizes 00 mm x 0 mm Tanalised 7 mm x 47 mm 7 mm x 40 mm Base Rail Aluminium Section Sizes 70 mm x 0 mm 37 mm x 4 mm NO ALUMINIUM OPTION Side Rail Aluminium Section Sizes 70 mm x 0 mm mm x 4 mm NO ALUMINIUM OPTION Type of Used Purpose made commercial fittings. U Bolts and/or Q Clips U Bolts / Q Clips / P Clips Gearbox operated 0 mm aluminium tube with, Imported, Imported Doors Commercial Aluminium Door 7 mm x 0 mm Timber 7 mm x 0 mm Timber mm - Flexible LDPE Tensioning System Northern / 3.mm wall thickness to give increased Up to 0mm of tensioning is available by Hoop Diameter 60.3 mm High Tensile* 60.3 mm 60.3 mm Number of Struts/Stabilizers per end. 8 6 7 Strut/Stabilizer Bar Diameter 0.8 mm High Tensile* 0.8 mm Ridge Bar Diameter 0.8 mm High Tensile* Main Crop Bar Diameter 0.8 mm High Tensile* 0.8 mm Crop Bar Hanger Diameter 3 mm High Tensile* Steel Size End Timber Sizes 7 mm x 7 mm Tanalised 00 mm x 0 mm 00 mm x 0mm Side Timber Sizes 00 mm x 0 mm Tanalised 7 mm x 47 mm 7 mm x 40 mm Base Rail Aluminium Section Sizes 70 mm x 0 mm 37 mm x 4 mm NO ALUMINIUM OPTION Side Rail Aluminium Section Sizes 70 mm x 0 mm mm x 4 mm NO ALUMINIUM OPTION Type of Used Purpose made commercial fittings. U Bolts and/or Q Clips U Bolts / Q Clips / P Clips Gearbox operated 0 mm aluminium tube with, Imported, Imported Doors Commercial Aluminium Door 7 mm x 0 mm Timber 7 mm x 0 mm Timber Every effort has been made to accurately represent the products of our competitors at the time of going to print. The findings above are based on information that is widely available on the internet. We suggest all customers research these finding before purchasing their own Commercial Polytunnel and not to base their decision on which supplier to select on the findings above. 30 ft Single Span mm - Flexible LDPE 9
Notes from our Structural Engineer What we do and why we do it. At we don t leave anything to chance. We only use the highest grade materials in all of our polytunnels and structures. On these pages, our Structural Engineer explains the materials we use, their grade and why we use them.. Ground Tubes 6. Foundations With ground tubes being in the ground, they are likely to be in contact with water for extended periods of time. We use heavier gauge ground tubes which are hot dip galvanised to reduce the chance of corrosion. Our ground tubes, with a wall thickness of 3. mm use over 70% more steel than the frame work to ensure the foundations are as capable of withstanding the forces applied ot them. We specify a mass concrete foundation for a number of reason, firstly the concrete provides additional protection to the ground tube steel. Secondly, the concrete block increases the surface area in contact with the ground, meaning the resistance to sliding and overturning is massively increased. Finally, the mass of the concrete helps resist the uplift created by high winds. Ground anchor plates are not capable of withstanding the same forces, so we don t use them. 7. Doors 8. Hoop Sections Aluminium doors are much stronger than timber doors. Timber will deteriorate over the years, whilst Aluminium will perform season after season. Aluminium doors can also be re-sheeted a lot easier than timber doors should need replacing. Many other polytunnel companies will supply hoops in 3, 4 or even pieced due to transport restrictions. However, each joint within the structure will create a weak point. They provide optional extra parts to strengthen these weak points. These extra parts are often referred to as storm bars. 4 8 7 Using as few hoop sections as possible keeps the structure as strong as possible. This is why at, we will ONLY supply hoops in sections and our hoops DO NOT need storm bars. Transport Restrictions. 3 9 6 0.. Crop bars stiffen up the structure during strong winds. They can also help keep the legs tied together under heavy snow. We use large diameter, high tensile steel to ensure the structure remain rigid under both wind and snow loads. Calculations on our ROBUS range show adding crop bars can increase the wind load capacity by up to 60% Commercial grade, weld fittings help keep the structure rigid under high winds reducing wear and tear on the cover, as well as ensuring our structures remain how we design them to be. 3. Bracings 4. Steelwork All our structures are supplied with 0 mm bracing to all corners. Providing large diameter, high tensile bracing in one piece ensures the structure stays rigid under high wind loads. All our framework is manufactured from high tensile pre-galvanised steel to give a stronger structure. Our steel is typically 48% stronger than standard structural steel, with material certificates available on request. 0 Because of our piece hoop, 90% of our structures are delivered using our own transport. This allows us to delivery larger items safely and securely. This also ensures your structure arrives complete and in good order. 9. Door Frames 0. Base Rails Our door frames are made from 7 mm x 7 mm timber which is tanalised for added durability. All door frame joints use steel plates to add to the joint strength. Our door frames also give extra strength in the gable ends for wind loads. Base rails are important as they hold the sheet on the structure. The stronger the base rail the tighter the sheet is likely to remain, resulting in a longer life span and better performance during strong winds.. A lot of other polytunnel supplier supply commercial polytunnels with anchor plates to secure them in the ground. At, we will NEVER recommend using anchor plates on a commercial polytunnel. Ground anchor plates typically require the foundation to be back-filled with loose soil, which is generally a lot weaker than compacted, historic soils. The weakened back-fill makes it a lot easier for the anchor plate to pull free of the foundation. to side winds, A mass concrete block has both a counter weight and a larger surface area in contact with the existing soil with which to resist the overturning moment, ground anchor plates rely solely on the interaction of the ground tube and the weakened back fill to resist the overturning. During winds, the hole is more likely to become tapered, allowing the tunnel to move and flex, therefore creating extra stresses within the components and increasing the risk of failure. Also the foundations do not just resist uplift, there will be an amount of overturning moment resisted by the foundation due
See what else we do. Ltd Mill Green Waterside Road Colne Lancashire BB8 0TA Tel: 08 8730 Fax: 08 87733 info@npstructures.co.uk npstructures.co.uk 06/-V