Product Description PLEXIGLAS HEATSTOP XT 4029 IR-reflecting acrylic (PMMA) sheets for domed and continuous rooflights The product and its advantages PLEXIGLAS HEATSTOP XT is an infrared-reflecting polymethyl methacrylate (PMMA) specially designed for the manufacture of domed rooflights. Extruded PLEXIGLAS sheets are provided with a co-extruded surface layer which contains pearlescent pigments free from heavy metals and is inseparably united with the PMMA substrate. As a result, PLEXIGLAS HEATSTOP XT can be cold-curved and thermoformed just like ordinary PLEXIGLAS XT. In incident light PLEXIGLAS HEATSTOP XT has a reddish blue shimmer, which becomes greenish in transmitted light. This colour has an iridiscent effect. The colour impression may vary, depending on viewing angle and lighting conditions. The HEATSTOP effect is achieved by reflection of a large portion of the incident sunlight, especially in the infrared region, but does not noticeably detract from the materials high light transmission. As a result, the heat buildup in the rooms below such rooflights is drastically reduced, while the lighting conditions remain more or less unchanged. Less money has to be spent on airconditioning when it is hot and the people at work under roofs glazed in this way feel more comfortable. The benefit of application PLEXIGLAS HEATSTOP XT is excellently suited for the construction of domed rooflights barrel vaults continuous rooflights in warehouses, factory units and business premises patio roofing roof ventilators for caravans...and wherever adequate light is required without any major heat buildup.
Due to its favourable light diffusion factor, PLEXIGLAS HEATSTOP XT permits no regular incidence of sunlight, thereby preventing brightness jumps and the resultant harsh shadows. This has a positive influence on the people at work in these rooms, since they ore not aware of the actual temperatures. In the case of double glazing, the exterior layer is made of PLEXIGLAS HEATSTOP XT and the interior layer of ordinary, clear-transparent PLEXIGLAS. Computer simulation The Institute of Lighting and Structural Engineering which is part of Cologne Polytechnic has performed computer simulations to assess the benefit of PLEXIGLAS HEATSTOP XT in comparison with ordinary glazing made of PLEXIGLAS XT White 01670. The calculation was made for a standard factory unit with double-glazed rooflights and daylight illumination according to DIN 5034. The statutory order an heat insulation of buildings with low indoor temperatures was additionally considered. The room temperature was never to drop below 16 C and never to exceed 26 C. The computer simulation under Central European climate conditions produced the following results: Results of the computer simulation at Cologne Polytechnic Rooflights of PLEXIGLAS XT White 01670 and PLEXIGLAS XT Clear Percentage of glazing in entire roof area 11% 17% Comparison of energy consumption 100% 104% Comparison of cooling requirement 100% 64% Comparison of solar load 100% 72% Hours at temperatures over 26 C without air-conditioning 272 186 Rooflights of PLEXIGLAS HEATSTOP XT and PLEXIGLAS XT Clear Although glazing of PLEXIGLAS HEATSTOP XT in rooflights causes a slight increase in heating costs, it cuts down the average annual air-conditioning cost by more than one third. If PLEXIGLAS HEATSTOP XT is used for factory units without air-conditioning, the time (between May and September) during which room temperatures of over 26 C are recorded reduces by 32 per cent. These values take into account that the number of rooflights with PLEXIGLAS HEATSTOP XT has to be increased in order to achieve the same daylight quotient as with standard glazing. When converting a factory from standard to HEATSTOP glazing over the same area, the cooling requirement is more than halved. In unventilated units, the occurrence of temperatures of over 26 C is reduced by 42%. These data and statements are based on computer simulation for glazing with flat sheets. Experiments have shown, however, that the difference to domed rooflights, despite the degree of stretching, is negligible.
PLEXIGLAS HEATSTOP XT : Spectral characteristics ρ(λ) = spektraler Reflexionsgrad = spectral reflectance α(λ) = spektraler Absorptionsgrad = spectral absorptance τ(λ) = spektraler Transmissionsgrad = spectral transmittance Lichtdurchlässigkeit = Transmittance Wellenlänge = Wavelength Reflexionsgrad = Reflectance sichtbarer Spektralbereich = visible spectral range infraroter Spektralbereich = infrared spectral range Working In addition to the advantages just described, PLEXIGLAS HEATSTOP XT has nearly the same physical properties as extruded PLEXIGLAS XT White 01670 and can be machined and thermoformed in an identical manner. Degrees of stretching up to about 20 % (e.g. domed rooflights) do not impair the heat-reducing effect, but the light transmission increases noticeably over that of flat sheets. PLEXIGLAS HEATSTOP XT is classified as normally flammable (B 2) with no burning droplets according to DIN 4102, also TP (b) when tested to BS 2782, method 508A. Availability PLEXIGLAS HEATSTOP XT Grade 4029 is available - in a size of 3050 x 2050 mm and - 2.5, 3 as well as 4 mm thick. Thicknesses from 2.5 to 8 mm as well as cut-to-size sheets can in minimum manufacturing quantities be supplied to order.
Sunlight, but without its heat! A comparison of various glazing systems with and without PLEXIGLAS HEATSTOP XT A comparison of the double-glazing systems PLEXIGLAS HEATSTOP XT + PLEXIGLAS XT Clear (fig. d) and PLEXIGLAS XT White 01670 + PLEXIGLAS XT Clear (fig. e) produced the following results: 1) The double glazing in figure d (HEATSTOP + Clear) transmits less light than that in figure e (White + Clear). 2) However, the light transmission decreases less drastically than the total energy transmission. If a room is assumed to have a flat-glazed roof area (White + Clear) of 11 per cent, this area must be enlarged to 17 per cent to achieve the same light intensity (luminosity) with HEATSTOP + Clear. Since domed rooflights with normal degrees of stretching up to about 20% show a markedly higher light transmission, their share of the roof area when made of PLEXIGLAS HEATSTOP XT will in practice be less than 17 per cent. 3) The annual heat quantity from the sunlight ('solar load') which enters through roof glazing with PLEXIGLAS XT HEATSTOP is 28% lower than in the case of smaller glazing areas with PLEXIGLAS XT White + Clear. Conclusion: Double glazing of PLEXIGLAS HEATSTOP XT in combination with PLEXIGLAS XT Clear provides the optimum of high light transmission with low total energy transmission. PLEXIGLAS HEATSTOP XT: Single glazing (a) A = PLEXIGLAS HEATSTOP XT Grade 4029 B = Incident sunlight C = Light transmission D = Reflection E = Energy transmission F = outwards directed... G = inwards directed...
H =... convection + heat dissipation PLEXIGLAS HEATSTOP XT: Single glazing (b) A = PLEXIGLAS XT Clear 20070 PLEXIGLAS HEATSTOP XT: Single glazing (c) A = PLEXIGLAS XT White 01670 PLEXIGLAS HEATSTOP XT: Double glazing (d) A = Double glazing with 1 = PLEXIGLAS HEATSTOP XT Grade 4029 2 = PLEXIGLAS XT Clear 20070
PLEXIGLAS HEATSTOP XT: Double glazing (e) A = Double glazing with 1 = PLEXIGLAS XT White 01670 2 = PLEXIGLAS XT Clear 20070 PLEXIGLAS HEATSTOP XT: Double glazing (f) A = Double glazing with 1 = PLEXIGLAS XT White 01670 2 = PLEXIGLAS XT White 01670 This document describes the special characteristics of PLEXIGLAS HEATSTOP XT. A separate Product Description on the general material properties of PLEXIGLAS XT basic grades (Ref. No. 231-1) is available from the stockist. = registered trademark PLEXIGLAS and PLEXIGLAS HEATSTOP are registered trademarks of Evonik Röhm GmbH, Darmstadt, Germany. Certified to DIN EN ISO 9001 (quality) and DIN EN ISO 14001 (environment) This information and all further technical advice is based on our present knowledge and experience. However, it implies no liability or other legal responsibility on our part, also with regard to existing third party intellectual property rights, especially patent rights. In particular, no warranty, whether express or implied, or guarantee of product properties in the legal sense is intended or implied. We reserve the right to make any changes according to technological progress or further developments. The customer is not released from the obligation to conduct careful inspection and testing of incoming goods. Performance of the product described herein should be verified by testing, which should be carried out only by qualified experts in the sole responsibility of a customer. Reference to trade names used by other companies is neither a recommendation, nor does it imply that similar products could not be used. Ref. No. 232-5 March 2000 Business Unit Performance Polymers Evonik Röhm GmbH Kirschenallee, 64293 Darmstadt, Germany. info@plexiglas.net www.plexiglas.net www.evonik.com