DESIGN & SIMULATED TEST: ROUND-UP
XENON ARC TESTING FOR PAPER AND TRANSPORT
L
ight fastness, or colour fastness to light, is the resistance of printed or pigmentedmaterials to fading or
colour change due to exposure to sunlight or an artificial light source. Smithers Pira tests for print fade and
lightfastness of paper, print and pigmented plastics using a JamesHeal Apollo weather fastness tester fitted with a xenon arc lamp source and irradiancemeasurement. Lightfastness testing ismade using
filtered xenon arc lamps which simulateUV and visible solar radiationmore closely than any other artificial light source. Xenon- aging testing provides the bestmethod for assessing the accelerated light ageing of products such as pigments, dyes and inks, which are sensitive to the long-wave and visible wavelengths of sunlight. With appropriate filters fitted, direct
sunlight, sunlight through window glass and in-store lighting conditions can be reproduced. A series of BlueWool standards are included with every set of test samples to ensure that results are reliable and reproducible. Accelerated weathering includes a
simulated rain cycle which can introduce an element of thermal shock to the test sample. There aremany international standards
applicable to lightfastness testing, including ISO 105-B02, BS EN20105-B02, BS EN 4892-2 and ISO 12040. The BlueWool standards included with each set of test samples conformto ISO 105-B01, BS EN 20105-B02 and BS 1006. Meanwhile, ElementMaterials
Technology has completed further investment in a new enhanced, accelerated weathering testing capability to the ASTM D7869 standard. ASTMD7869 is a xenon arc-method that allows transportation clients tomore accurately reflect weathering cycles of high intensity sun and moisture.With this new capability, Element is positioned to keep pace with the evolution in the automotivemarket, which ismoving towardsmore complex testing standards. ElementNew Berlin is an ISO 17025-accredited laboratory and holds A2LA ASTMD7869 accreditation. This newtest is part of a suite of
environmental exposure tests offered by Element in the transport sector, including temperature and humidity cycle testing, salt spray/fog andUV radiation exposure testing.
SEMI-ANECHOIC CHAMBER HAS DESIGNED CUT-OFF FREQUENCY
M
erfordNoise Control has designed and installed a “semi-anechoic” chamber with a designed cut-off
frequency of 63Hz for acoustics researchers at GhentUniversity in Belgium. A semi-anechoic chamber features a
solid, non-sound-absorbing floor – only the walls and ceiling are acoustically absorbent. The solid floor allows equipment to be placedmore easily than is the case with a fully anechoic facility. The new acoustic measuring chamber is one of only four such facilities available to researchers throughout Belgiumand theNetherlands. Designed to eliminate internal sound
reflections and provide isolation from external sound sources, the chamber is located in the basement of a new faculty building at Ghent and is essentially a box-
Solid floor chamber provides semi-anechoic capabilities for Ghent researchers, below; and accelerated weathering brings new test capabilities to the automotive industry
within-a-box, the floating floor arrangement ensuringminimal intrusion of sound transmissions fromthe outside. Access to the chamber is via a double-door that includes an acoustic lock on both sides; the doors are constructed so as to be internally sound absorbent. The walls and the ceiling of the new
chamber are lined with approximately 1,000 wedge-shaped sound absorbing elements constructed frommelamine foam. Each wedge has a design length of 1.20 metres in order to achieve the specified 63Hz cut-off
frequency.Depending on the nature of themeasurements and the researchers’ requirements, the floor can also be covered with absorbent panels to improve the overall acoustic performance of the chamber. For this project,Merford developed an
advancedmounting systemfor the acoustic absorbent wedges, which allows the researchers to quickly replace those that are damaged during research activities. Mounting accuracy for the wedges is of particular aesthetic importance for this type of chamber, withmillimetre tolerances having to bemet both horizontally and
vertically.Merford achieved this by designing a special clamping systemthat ensures precise, instantaneous alignment of the wedges when inserted. The construction of semi-anechoic
chambers is one aspect ofMerford’s business, which encompasses a broad field of testing facilities, industrial noise control and the application of innovative sound attenuation techniques. The company has built similar semi-anechoic sound measurement chambers for aircraft manufacturer Airbus and power tool manufacturer Stihl. The GhentUniversity semi-anechoic
chamber design and construction contract was awarded toMerfordNoise Control following a European tender. EE
April 2017 /// Environmental Engineering /// 39
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