British Standard BS Research Articles

Experimental investigation and design of longitudinal shear reinforcement in composite edge beams

The development of a new reinforcing component is reported. Its primary function is to prevent a special type of longitudinal shear failure from occurring in composite edge beams when profiled steel sheeting is laid transverse to the longitudinal axis of the steel beam, and welded-stud shear connectors are fastened through the sheeting either directly or in pre-cut holes. This brittle failure mode, referred to in the literature as a rib shearing failure, comprises horizontal splits that form in the concrete between the tops of the steel ribs in pans where there are shear connectors, while the failure surface locally avoids the studs by passing over their heads. It has been reported in the literature to have occurred on numerous occasions in push-out and beam tests, and is even shown to occur in tests on beams incorporating typical Australian profiled steel sheeting products with narrow, widely spaced steel ribs, and detailed in accordance with British Standard BS 5950, Part 3.1 and Eurocode 4, Part 1.1. It is now mandatory in Australian Standard AS 2327, Part 1 to reinforce against rib shearing failure. Other potentially important applications for the reinforcing component are also described.

Effects of shielding gases on weld diffusible hydrogen contents using cored wires

Cored wire welding is widely used for joining thick steel sections, where a high integrity weld is required. The shielding gases selected for cored wire welding depend on the type of filling constituents of the wire. Weld properties, deposit chemistry, bead shape, deposition rates, and the operational characteristics of weld ing are greatly affected by the shielding gases. In the present work, studies have been carried out to observe the effects of wide ranging shielding gases on the diffusible hydrogen contents of welds using cored and solid metal inert gas (MIG) welding wires. The hydrogen present in the weld metal has been determined by the method described in British Standard BS 6693: 1988. For flux and metal cored wires, it was observed that an increase in shielding gas CO2 content has a marked effect on diffusible hydrogen and, for both consumables, the diffusible hydrogen content decreases as the CO2 content increases in Ar–CO2 mixtures. The effects of weld penetration and metal transfer, by changing the shielding gas, on hydrogen content of the weld metal have also been studied and reported.

Comparison of experimental assessment methods to estimate the strength of gear teeth

Regression type methods for analysing proportions, known as probit and logit analyses, are compared with the British Standard BS 3518 (part 5) recommendations for analysis of staircase designs. All these methods are found to give similar results. Different experimental strategies, involving fixed sample sizes for load levels chosen in advance, are compared with staircase designs. Recommendations for practice are made. Finally, the versatility of the logit analysis for investigating the effects of additional variables, such as additional treatments during manufacture, is demonstrated through a case study.

Evaluation of a transient test procedure for solar flat-plate collectors

A dynamic method for testing solar flat-plate collectors under unsteady weather conditions has been validated through detailed experiments and compared with two established standards: the ASHRAE 93–86 standard for steady state testing and the British standard BS 6757 for transient testing. The new method is based on a lumped capacity model derived from a general energy balance of the collector under actual conditions. The characteristic parameters are estimated using the standard methods for unconditional non-linear optimisation. Extensive experiments have been carried out under a wide range of operating and environmental conditions. Four different collectors commercially available in the market have been tested at the same location and using the same experimental rig. The results on the basis of the new method are very close to those obtained from the ASHRAE standard. The average values of F R( τα) e and F R U L by the new method are within ±3% of the steady state values. The results of the BS 6757 method are within ±2% for F R( τα) e but those of F R U L are about 12% lower than the ASHRAE values. On average, the difference between the theoretical predictions for the outlet temperature by the new method and the corresponding experimental measurements are about ±0.3°C, while the predictions by the British standard under the same conditions are about 2°C lower than measured values. The percentage deviations of predictions for the temperature rise based on the two methods, averaged over a day, are about ±8% and ±36% respectively. The new dynamic method requires less time for experimentation, one day's test is enough to give accurate estimation of the collector parameters. The method does not impose any restriction on the variation of weather or operating parameters and, therefore, has a quite general applicability.

The application of geographic and land information systems to the management of local authority property

Since the Audit Commission’s report on local authority property management in 1987 and subsequent publications, there has been substantial investment in geographic and land information systems (GIS/LIS) by local government. This paper reviews the issues associated with the uptake of information technology (IT) for property management within local government, taking the Audit Commission’s findings as its starting point. It considers how authorities have taken up new technologies and describes progress in this area. British Standard BS 7666 for geographical referencing presents new opportunities for integrated property management in local authorities. The paper discusses this development, drawing on examples from local authorities. The paper concludes by examining the Western Australian Land Information System (WALIS). This is an example of how information sharing between local and central government organisations can add value to data sets collected and maintained by each, reduce duplication of effort and offer a more consistent service.

Design resistance of unstiffened column web subject to transverse compression in beam-to-column joints

Buckling of column web was responsible for failure of a large number of bolted end plate connections tested at the University of Abertay, Dundee. The British Standard BS 5950 and the draft European Standard EC 3 contain design rules for determining the resistance of unstiffened column web of bolted beam-to-column joints subject to local transverse compression. These design rules are appraised by comparison with the test results.

Performance of respiratory filters and surgical masks against bacterial aerosols

A laboratory test system has been designed and built to measure the efficiency of filter material from several commonly used respirator filter cartridges, approved disposable dust masks, nuisance dust masks, single-use surgical procedure masks and a resuscitation mask against aerosols of the bacteria Bacillus subtilis subspecies globigii, Micrococcus luteus and Pseudomonas alcaligenes. All tests were carried out at a flow rate of 301min−1. The same materials were also tested with monodisperse urea aerosols in the size range 1.5–9 μm and with the British Standard BS 4400 sodium chloride aerosol, which has a mass geometric mean diameter of 0.6 μm and a geometric standard deviation of 2.3. One type of surgical mask allowed penetration of up to 83% of a microbiological aerosol and 87% of a non-biological aerosol, and nuisance dust masks allowed penetrations of up to effectively 100% for a microbiological aerosol and 91% for a non-biological aerosol. The materials of the other surgical masks and the resuscitation mask, all of which were electrically charged, performed better against all the test aerosols. Penetration of microbiological aerosols through the respirator filter materials was no greater than 0.88%, and penetration of non-biological aerosols no greater than 1.72%. The results for microbiological aerosols generally corresponded to those for the non-biological aerosols in the same size range.

Mechanical properties of welded joints in thin walled aluminium extrusions

The present work describes the tensile properties of weldments in thin walled extruded Al–Mg–Si alloys. Tungsten inert gas (TIG), metal inert gas (MIG), and friction stir (FS) welding are considered. Properties of joints welded with different filler metals are presented, both matching and undermatching the parent materials in strength. The weldments were tested in both as welded and post-weld aged conditions. It is shown that silicon rich filler metals (Al–5Si and Al–12Si) were adequate for the welding of 6063 alloy but did not give welds with strength sufficient to match that of 6082 alloy. Tungsten inert gas welding resulted in large heat affected zone (HAZ) widths of 20 mm, compared with HAZ widths of 10 and 8 mm for MIG and FS welding respectively. This relationship was also seen in tensile tests where FS specimens exhibited the highest strength and TIG specimens exhibited the lowest strength. The post-weld aged materials recovered some strength, with increases in tensile strength of 10–15% for 6063 alloy and of 20% for alloy 6082 compared with the strengths of the as welded specimens. Comparisons between experimental data and two design codes, a draft European standard and the British standard BS 8118, show that the European standard is conservative for welds in thin walled material. Standard BS 8118 describes MIG and FS HAZ widths well but underestimates the HAZ width for TIG welds.

Rationale for the introduction of environmental management systems to local government, environmental regulators and industry — a case study

Under the technical assistance programme of the Environmental Know How Fund, an environmental management training course, based on British Standard BS 7750 (BSI, 1994), was developed and delivered to local government, environmental regulators and industry in Kamensk-Uralsky, Russia. The case study approach to training middle managers incorporated environmental reviews of workshops within three large industrial plants. One such environmental review is described here to illustrate problems and fundamental differences in integrating Western and Former Soviet Union (FSU) principles on management, legislation and pollution control. The paper considers whether current pollution measures and environmental auditing procedures would satisfy the needs of the international community funding and trading with Russian industry, and concludes that a structured environmental management system (EMS) approach is required. There is little doubt about the benefits of implementing an EMS, both in terms of pollution reduction and overall cost savings; however, the crucial first step of the EMS approach, commitment from top management has yet to be established. © 1997 by John Wiley & Sons, Ltd and ERP Environment.

Strain gauge proof hydraulic testing of commercial pressure vessels

AbstractSome aspects of the philosophy of shakedown are presented relevant to the requirement of the British pressure vessel code British Standard BS 55(X): 1994 for proof hydraulic pressure tests on vessels containing features not covered in the design rules within BS 55(X). The difficulties in achieving the objective of the test are discussed. Examples are provided from the experiences gathered from such proof hydraulic tests on over 50 commercial pressure vessels.

Short reviews

Book review in this Article Food Colour and Appearance. By John B. Hutchings. Glasgow: Blackie. 1993. Pp. xii + 513. ISBN 0 7514 0176 5. 95.00. Industrial Chocolate Manufacture and Use British Standard BS 4317: Part 29: 1993 (ISO 11050: 1993). Determination of impurities of animal origin in wheat flour and durum wheat semolina. Milton KeynesBritish Standard BS 7087: Part 18: 1993. Herbs and spices ready for food use. Part 18. Specification for dried rosemary (whole British Standard BS 6002: Part 1: 1993 (ISO 3951: 1993). Sampling procedures for inspection by variables. Part 1. Specification for single sampling plans indexed by acceptance quality level (AQL) for lot‐by‐lot inspection. Milton Keynes British Standard BS 4285: Part 3: Methods for detection and/or enumeration of specific groups of microorganisms. Section 3.15. (ISO 10560: 1993). Detection of Listeria monocytogenes. Milton Keynes

Wind velocities over pitched roofs

This paper describes wind-tunnel investigations of the wind velocity field over the roof of a model of the Aylesbury experimental house, and gives examples of data. The range of velocity variation was found to be much smaller than that of local pressure coefficients, with no consistent correlation between C p and V/V ref . The velocities were lower than predicted by the current British Standard code BS 5534 for slating and tiling. This is traced to flawed logic in the method of estimation used in the code. An empirical amendment to the currently used method of estimating local velocities is given. This gives a reasonably good fit to measured data in the central area of the roof.

ASSESSMENT OF EXISTING HIGH ALUMINA CEMENT CONSTRUCTION IN THE UK.

After a few collapses in the early 1970s, reference to high alumina cement concrete (HACC) was deleted from the Code of Practice for the use of structural concrete (CP 110) which is now embodied in the current British Standard BS 8110. This paper gives the background to the current guidance for the assessment of HAC construction, and updates the advice to take account of developments and further research which has taken place since 1975. The majority of new information has come from site investigations of specific structures, and a number of findings have emerged which have a bearing on how appraisals of HAC construction should be considered. The main conclusions are that in the absence of chemical attack, the strength assessment guidance issued in 1975 by the Building Regulations Division of the Department of the Environment has been shown to be safe without being over-pessimistic, but that the risk of corrosion to reinforcement is becoming an increasingly important consideration in the assessment of HAC components. A materials testing regime is described in this paper which has been devised in order to identify cases of chemical attack and to assess the current level of protection afforded to the reinforcement.

Gas sensing for fire detection: Measurements of CO, CO 2, H 2, O 2, and smoke density in European standard fire tests

Measurements were made of the concentration of various gases during the course of six types of fire that conform to the British Standard BS 5445 part 9 (which is identical to the European Standard CEN- 54). It is shown that a ‘chemical fire detector’ that has good performance in all of the six test fires could be made by the measurement of certain gases. In addition, analysis of the output from the various signals could provide further information about the state of, and type of, fire, thereby reducing the risk of false alarms. The use of a chemical fire detector could therefore improve current fire detection systems.

Book reviews

Therapeutic Properties of Fermented Milks.Flour Confectionery Manufacture.Sensory Evaluation Practices.Capillary Elecrophoresis.Modern Methods in Food Mycology.Food Packaging: Principles and Practice.Low‐Calorie Foods Handbook.British Standard BS 4585: Part 6: 1992.British Standard BS 4325: Part 9: 1992.Toxicological Evaluation of Certain Food Additives and Naturally Occurring Toxicants.Toxicological Evaluation of Certain Veterinary Drug Residues in Food.Listing of Codes of Practice Applicable to Foods.McCance & Widdowson: A Scientific Partnership of 60 Years.Oxidative Enzymes in Foods.

Dynamic Testing of the Strength of Helmet Chin Straps

Abstract A dynamic test of-chin strap strength was introduced into the British Standard BS 2495 in 1980. This test has subsequently been adapted for bicycle and horse riding helmets without the same correlation between accident and test failures being established. The causes of force peaks and oscillations in the test traces have been identified, and a means was found of obtaining reliable chin strap force measurements. Recommendations are made for improving the test so that chain straps and buckles are adequately strong but not over-designed.

The incidence and prevention of ocular injuries in orthodontic practice.

A postal survey was conducted to determine the use of eye protection and incidence of ocular trauma in orthodontic practice. One-hundred-and-fifty-nine NHS orthodontic consultants and 203 specialist orthodontic practitioners were surveyed. Two-hundred-and-forty-one (66.5 per cent) replies were received. Some form of eye protection was routinely worn by 66.8 per cent of orthodontists, 64.3 per cent of patients, but only 33.6 per cent of DSAs. Eye protection was not offered to DSAs in 31.9 per cent of practices or to patients in 22.1 per cent. Forty-three per cent of orthodontists reported instances of ocular injury in their practices. The majority of these injuries (n = 104) occurred during debonding or trimming acrylic. Other incidents involved ligating materials, intra-oral polishing, and acid etching. Most injuries (83.5 per cent) were treated in the surgery without any long-term effects. The routine use of goggles or spectacles with side-pieces and plastic lenses, which conform to British Standard BS 2092, is recommended for staff and patients during all operative procedures in orthodontic practice.

Long-term strains measured in reinforced concrete building

Strains measured over a period of 17 years are reported for a reinforced concrete building. Vibrating wire strain gauges were embedded in the ribs and beams of the first floor of a three-storey telephone exchange in south-west England. Groups of gauges were located at mid-span of two 170 mm thick ribs, at mid-span of a 470 mm thick beam, and near the support column and edge beam of the 470 mm thick beam. Gauges in each group were positioned at different depths in the direction of the expected stress and transversely, so that shrinkage and load-induced strains could be calculated. Concrete temperatures and relative humidities were measured so that allowance could be made for the small variations of thermal strain and changes in drying conditions. Elastic modulus, weight loss and strain measurements were undertaken on site-stored and laboratory-stored prisms cast from the in situ concrete. n e embedded vibrating wire strain gauges enabled the strains to be measured sensitively and reliably over the 17 year period of observation. It took about 10 years for drying shrinkage to reach approximate equilibrium, but some additional shrinkage was then observed owing to change in use of the building. There was only approximate agreement between the measured shrinkage strains and those estimted from British Standard BS 81l0: Part 2: 1985. The normal pattern of flexural strains in the floor was superimposed by a tensile strain component that seemed to arise from the restraint of drying shrinkage.

Plate slenderness limits for high strength steel sections

Abstract The paper describes a test programme on stub columns fabricated from BISALLOY 80 steel plates with nominal yield stress of 690 MPa. The programme comprises 18 box, cruciform and I-section specimens. The slenderness of the component plates are chosen in the vicinity of the yield slenderness limit, beyond which the stub column strength is reduced below the squash load as a result of local buckling. The purpose of the tests was to determine whether the yield slenderness limits used in the Australian Steel Structures Standard AS 4100 are applicable to BISALLOY 80 steel plates. The paper also assesses whether the plate strength rules of the Australian Steel Structures Standard AS 4100, the Load and Resistance Factor Design Specification of the American Institute of Steel Construction (AISC-LRFD), the British Standard BS 5950 Part 1 and the European Convention for Structural Steelwork Eurocode3 are applicable to high strength steel. For this purpose, the plate strength curves of these specifications are compared with the BISALLOY 80 test results and with test results from the USA and Japan on high strength steel plates with nominal yield stress of 690 MPa.

Composite columns of double-skinned shells

Abstract Tests were carried out on 12 hollow circular columns of composite shell walls with a view to investigating their behaviour when subjected to eccentric end compressive forces. The cross-section of the columns consists of two concentric thin steel shells, and the ring-shaped space between then is filled with either grout or microconcrete. The columns have a buckling length of about 4 m, and the results of the tests are reported here. The experimental failure loads are compared with the predictions of the British Standard BS 5400, and also with the results of a finite element analysis. The test results reported here confirm the viability of such novel columns as a practical solution to unusual situations. The results also emphasize the need for experimental investigations before the application of the British Standard BS 5400 to the design of composite columns of unusual cross-sections.