Parallel and Serial Methods of Calculating Thermal Insulation in European Manikin Standards

Abstract

Standard No. EN 15831:2004 provides 2 methods of calculating insulation: parallel and serial. The parallel method is similar to the global one defined in Standard No. ISO 9920:2007. Standards No. EN 342:2004, EN 14058:2004 and EN 13537:2002 refer to the methods defined in Standard No. EN ISO 15831:2004 for testing cold protective clothing or equipment. However, it is necessary to consider several issues, e.g., referring to measuring human subjects, when using the serial method. With one zone, there is no serial-parallel issue as the results are the same, while more zones increase the difference in insulation value between the methods. If insulation is evenly distributed, differences between the serial and parallel method are relatively small and proportional. However, with more insulation layers overlapping in heavy cold protective ensembles, the serial method produces higher insulation values than the parallel one and human studies. Therefore, the parallel method is recommended for standard testing.     

Calculation of clothing insulation by serial and parallel methods: effects on clothing choice by IREQ and thermal responses in the cold.

Cold protective clothing was studied in 2 European Union projects. The objectives were (a) to examine different insulation calculation methods as measured on a manikin (serial or parallel), for the prediction of cold stress (IREQ); (b) to consider the effects of cold protective clothing on metabolic rate; (c) to evaluate the movement and wind correction of clothing insulation values. Tests were carried out on 8 subjects. The results showed the possibility of incorporating the effect of increases in metabolic rate values due to thick cold protective clothing into the IREQ model. Using the higher thermal insulation value from the serial method in the IREQ prediction, would lead to unacceptable cooling of the users. Thus, only the parallel insulation calculation method in EN 342:2004 should be used. The wind and motion correction equation (No. 2) gave realistic values for total resultant insulation; dynamic testing according to EN 342:2004 may be omitted.     

Calculation of Clothing Insulation by Serial and Parallel Methods: Effects on Clothing Choice by IREQ and Thermal Responses in the Cold

Cold protective clothing was studied in 2 European Union projects. The objectives were (a) to examine different insulation calculation methods as measured on a manikin (serial or parallel), for the prediction of cold stress (IREQ); (b) to consider the effects of cold protective clothing on metabolic rate; (c) to evaluate the movement and wind correction of clothing insulation values.

Tests were carried out on 8 subjects. The results showed the possibility of incorporating the effect of increases in metabolic rate values due to thick cold protective clothing into the IREQ model. Using the higher thermal insulation value from the serial method in the IREQ prediction, would lead to unacceptable cooling of the users. Thus, only the parallel insulation calculation method in EN 342:2004 should be used. The wind and motion correction equation (No. 2) gave realistic values for total resultant insulation; dynamic testing according to EN 342:2004 may be omitted.     

A Comparison of Two Methods of Determining Thermal Properties of Footwear

The present European Standard for footwear testing (Standard No. EN 344:1992; European Committee for Standardization [CEN], 1992) classifies footwear thermally by a temperature drop inside the footwear during 30 min at defined conditions. Today, other methods for footwear thermal testing are also available. The aim of this study was to compare EN 344:1992 with a thermal foot method. Six boots were tested according to both methods. Additional tests with modified standard tests were also carried out. The methods ranked the footwear in a similar way. However, the test according to standard EN 344:1992 is a pass-or-fail test, whereas data that is gained from the thermal foot method gives more information and allows further use in research and product development. A change of the present standard method is suggested.     

让实验室测试值更贴近真实世界防护值——护听器的声衰减值评价方法讨论

本文介绍了护听器声衰减值的评价方法,对比了我国、ISO、欧洲EN、美国ANSI和澳大利亚新西兰AS/NZS标准中关于护听器声衰减值评价方法的差异。着重讨论在测试过程中,使用不同的受试者和护听器佩戴方式得出的检测数据与真实世界防护值的一致性情况。研究表明,使用"受试者自行佩戴"的方式测得的数据能更好地反映护听器在真实世界的防护性能。     

Testing Sleeping Bags According to EN 13537:2002: Details That Make the Difference

The European Standard on sleeping bag requirements (EN 13537:2002) describes a procedure to determine environmental temperature limits for safe usage of sleeping bags regarding their thermal insulation. However, there are several possible sources of error related to this procedure. The main aim of this work was to determine the influence of the various measuring parameters on the acuity of the respective parameters in order to judge the requirements. The results indicated that air velocity, mattress insulation and time between unpacking the bag and measurement had a significant impact on the result, with a difference of up to 5–15% in thermal insulation between minimum and maximum allowable parameter levels. On the other hand, manikin weight, thickness of the artificial ground and presence of a face mask were found to have a negligible influence. The article also discusses more general aspects of the standard including the calculation methods used.     

BS EN ISO 20345：2011《个体防护装备安全鞋》标准的解析和建议

本文通过对最新的BS EN ISO 20345：2011《个体防护装备安全鞋》标准的列表介绍和概括性分析,找出了新标准检测项目仍存在的遗留问题和未考虑到的缺陷以及需要界定的术语,并提出了今后标准的再修订意见。此再修订意见的给出,为推动今后与安全鞋标准BS EN ISO 20345：2011属于同一体系的我国GB 21148-2007《个体防护装备安全鞋》标准修订提供参考意见。     

聚苯乙烯外墙保温系统火灾风险影响因素分析

为了研究聚苯乙烯外墙保温系统火灾风险的问题,对比了3种火灾测试方法,分别是基于ISO 5660的小尺寸锥形量热计实验方法、基于ISO 9705的大尺寸实验方法和基于BS 8414的全尺寸实验方法。讨论了3种方法评测外墙保温系统火灾风险的适用性,进一步在比较分析热释放速率、临界热流强度、火蔓延情况、火灾行为以及实验后样品完整性等参数的基础上,得到了影响聚苯乙烯外墙保温系统火灾风险的关键因素。结果表明:虽然空腔的形成在此类系统火灾中不可避免,但系统保护层的严密性和完整性决定了空腔火蔓延的危险性以及聚苯乙烯在系统内的融化流动及燃烧特性。针对聚苯乙烯外墙保温系统火灾风险影响因素,进一步给出了此类系统的防火措施。     

焊接防护具抗热穿透性能测试仪的研制

焊接防护具是指一种保护佩戴者免受由焊接或相关作业所产生的有害光辐射及其他特定有害因素的装置。它是从事焊接与热切割作业人员必备的个体防护装备。抗热穿透性能是表征焊接防护具产品质量和安全性能的最重要技术指标之一。然而,如何快速、便捷、节能、准确地对焊接防护具抗热穿透性能进行检测,是迫切需要解决的技术难题。本文在简要分析国内外眼面部防护标准中抗热穿透性能技术要求和测试方法的基础上,提出了一种测试焊接防护具抗热穿透性能的方法,并成功研制了焊接防护具抗热穿透性能测试仪。     

The Relationship Between the Difference in Prismatic Refractive Power of an Eye-and-Face Protector and Its Thickness,Radius of Curvature,and Material

With the help of the research results presented here and on the basis of a graphic analysis we aim to prove the existence of a relationship between the difference in prismatic refractive power and the thickness, curvature radius, and type of material used for panoramic oculars in protective spectacles, goggles, and face shields. The difference in the prismatic refractive power is a fundamental optical characteristic of a protective ocular without corrective effect. According to Standard No. EN 165:1995 (European Committee for Standardization, 1995) the difference in the prismatic refractive power is a difference in the prismatic effect at 2 observation points of an eye-protector.     

Ergonomics Oriented to Processes Becomes a Tool for Continuous Improvement

Abstract

A holistic view is essential for quality initiatives such as Total Quality Management (TQM), Standard No. ISO 9001:1994 (International Organization for Standardization [ISO], 1994), Concurrent Engineering, Business Reengineering, and Business Process Improvement. The challenge is knowing how to transition from this theoretical concept to implementation. The relationship between quality interest and anergonomics program will be the focus of this discussion. An ergonomics oriented improvement program includes (a) ergonomics or fitting the job to the person; (b) integration of operations management, safety engineering, medical management, and employees as co-owners of the process; (c) the emphasis of ergonomic precepts in the engineering of new processes and improvement of current processes; and (d) the emphasis of employees taking responsibility for their own well being and the improvement of their work environment. The parallel between the continuous improvement process delineated by the quality-system requirements in Standard No. ISO 9001:1994 (ISO, 1994) and the improvement contributions of ergonomics are very revealing (Getty, Abbott, & Getty, 1995). It is the contention of this approach that if the precepts of ergonomics were applied to the work environment, it would support the objective of world class quality and productivity, resulting in improved global competitiveness of businesses.     

Determination of Heat Loss from the Feet and Insulation of the Footwear

This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of thermal foot method, the latter should be preferred for testing.     

Degradation of fluorescent high-visibility colors used in safety garments for the Australian railway industry

IntroductionThis study investigated the compliance of four fluorescent orange high-visibility garment substrates that are predominantly used in the Australian railway industry. While Special Purpose Orange (SPO), a shade of the Fluorescent orange (Fl-orange) is recommended by most Australian states as the high-visibility background color of a safety garment, there appear to be variations in the background color of clothing used by line-workers and rail contractors. The color of the garment was assessed for compliance with the Australian Standard AS/NZS 1906.2.2010 for high-visibility materials for safety garments. The results were also compared with ANSI Z535.2011 and BS EN ISO 20471.2013 Standards.MethodPhotometric and colorimetric assessments of the background color of the garment substrates were performed using a spectrophotometer and were evaluated for compliance with the Standards after washing and exposure to UV.ResultsThe spectrophotometry measurements showed that Fl-orange background color for all samples except one complied with the AS/NZS 1906.2 Standard for daytime high-visibility garments after 20 washes but failed to comply after exposure to UV. It was also found that the chromaticity coordinates of the corners of the Fl-orange color space, specified in the AS/NZS 1906.4.2010 Standard are much wider and yellower when compared with the ANSI Z535.1.2011 and BS EN ISO 20471.2013 Standards. The sample that failed to comply with the Australian and American Standards however complied with the ISO Standard.Practical ApplicationsIrrespective of the Standard used, the research has shown the degrading effect of washing and light exposure and raises the questions as to how regularly, and under what conditions high-visibility garments need to be replaced. These findings will provide information for safety garment manufacturers about the characteristics and performance of high-visibility safety garments which make them conspicuous during daytime use. This research recommends that colors for railway workers should be chosen based on the conspicuity, commercial viability, reproducibility and durability rather than simply adopting standards from other industry domains or other countries.     

Physiological Method of Evaluating Protective Clothing for Work in a Cold Environment

The purpose of this study was to determine the usefulness of physiological studies in the evaluation of protective clothing for work in a cold environment. The study included the examination of the dynamics of changes in chosen physiological parameters (core and skin temperatures, heart rate, pulmonary minute ventilation) as well as physical ones (the temperature and relative humidity under the clothes) during work in protective clothing with unknown thermal insulation. The experiment was conducted in extreme environmental conditions (–10 and –15°C) at a work load defined by the clothing manufacturer as moderate. Results show that thermal equilibrium was achieved and maintained throughout the investigated work time (60 min) and that the protective clothing ensures safety on the time scale of a regular 8-hour work day. It was also shown that the dynamics of thermal stress physiological parameters can be used to determine the maximum duration of exposure for cold protective clothing with unknown thermal insulation.     

The use of footwear insulation values measured on a thermal foot model.

The use of physiological data from human tests in modelling should consider background data, such as activity, environmental factors and clothing insulation on the whole body. The present paper focuses on local thermal comfort of feet with special attention on the effects of physical changes of footwear thermal properties. An alternative test method is available for footwear thermal testing besides the standard method. The possibility to use insulation values acquired on a thermal foot model in practice is shown here. The paper describes the correlation between cold and pain sensations, and foot skin temperatures of the subjects and relates these to insulation measured on a thermal foot model. Recommendations are made for footwear choice according to environmental temperature.     

Validation of the principles of injury risk zones for motorcycle protective clothing

IntroductionThe distributions of motorcycle crash impacts and injuries were compared to the four impact risk zones and protective performance specified in the European Standard for motorcycle clothing (EN 13595).MethodsCrashed motorcyclists' (n = 117) injuries and clothing damage were categorized by body area into the four risk zones. Three levels of protection were defined: protective clothing with impact protection, protective clothing only and non-protective clothing.ResultsThe distribution of impact/injury sites corresponded to the predictions of EN 13595, with the proportion of all injuries decreasing from 43.9% in Zone 1, to 18.0%, 16.7%, and 11.5% in Zones 2 to 4, respectively. Protective clothing modified the distribution of injuries with substantially more injuries (OR = 2.69, 95% CL: 20.1–3.59) at unprotected impact sites.Practical applicationThese findings support an appropriate framework for determining performance specifications for the manufacture of motorcycle clothing that will effectively reduce the risk of injury in crashes.     

Thermal manikin measurements--exact or not?

According to the European prestandard ENV 342:1998, the thermal insulation of cold-protective clothing is measured with a thermal manikin. Systematic studies on the reproducibility of the values, measured with different types of clothing on the commonly used standing and walking manikins, have not been reported in the literature. Over 300 measurements were done in 8 different European laboratories. The reproducibility of the thermal insulation test results was good. The coefficient of variation was lower than 8%. The measured clothing should fit the manikin precisely, because poorly fitting clothing gave an error in the results. The correlation between parallel and serial insulation values was excellent and parallel values were about 20% lower than serial ones. The influence of ambient conditions was critical only in the case of air velocity. The reproducibility of thermal insulation test results in a single laboratory was good, and the variation was lower than 3%.     

A case study: An explosion in a milk spray dryer,CAPSA, NW Spain

European Standard EN 14491 (2006): “Dust explosion venting protective systems”, based on German Standard VDI 3673 (2002): “Pressure venting of dust explosions”, Verein Deustcher Ingenieure, specifies the basic design requirements for the selection of dust explosion venting protection systems.In this study an investigation into the efficiency of venting surfaces in accordance with Standard EN 14491 has been undertaken to check the validation of the same. Thus, the application of the standard to an actual case of an explosion in a milk spray dryer has been studied, taking into consideration the explosive characteristics of products treated in this type of installation and their venting requirements.The results obtained indicate that, in specific situations – such as the effects of turbulence, particularly in the cone, or dust layer self-ignition – the European Standard could underestimate the venting surface requirements needed to alleviate possible excess internal pressure in order to avoid injury or structural damage to spray dryers.     

Dynamic Strength Tests for Low Elongation Lanyards

Lanyards are still important and common components of personal systems protecting against falls from a height. Experience with dynamic strength tests of lanyards indicates that test methods based on EN and ISO standards do not make objective assessment possible. This paper presents the results of theoretical and laboratory investigations of the performance of adjustable lanyards during fall arrest. The obtained results indicate that methods of testing and assessment based on those standards demonstrate considerable shortcomings when applied to low elongation lanyards. The assumptions for improved requirements and test methods of lanyards made of e.g., steel wire and aramid ropes are also presented.     

Dynamic strength tests for low elongation lanyards.

Lanyards are still important and common components of personal systems protecting against falls from a height. Experience with dynamic strength tests of lanyards indicates that test methods based on EN and ISO standards do not make objective assessment possible. This paper presents the results of theoretical and laboratory investigations of the performance of adjustable lanyards during fall arrest. The obtained results indicate that methods of testing and assessment based on those standards demonstrate considerable shortcomings when applied to low elongation lanyards. The assumptions for improved requirements and test methods of lanyards made of, e.g., steel wire and aramid ropes are also presented.