Bergamaschi A, Grandi C, D'Addato M, Di Carlo V, Russo A
Cattedra di Medicina del lavoro, Università degli Studi di Roma Tor Vergata.
G Ital Med Lav. 1995 Jan-Nov;17(1-6):41-9.
With the exception of domestic rooms, Overhead Radiant Tube Heaters (ORTH) are an effective system for indoor heating (e.g. warehouses, factories, garage workshops, shipyards, greenhouses, schools hall etc.). The growing number of units installed is due to several advantages, such as uniform heating, absence of air movements, energy saving, versatility and safety. Indoor heating is obtained by an infrared emission, which is produced by the circulation of combustion exhaust gases within tubes and is collected by a set of reflecting surfaces located around the tubes. In the present communication, the attention is driven on the characteristics of ORTH infrared emissions, with reference to potential health risks for the exposed people (especially people working within areas heated by this system). A reason for this is represented by the existence of a specific italian regulation (Circolare N. 1322/4134-28.01.1992, Direzione Generale della Protezione Civile-Ministero dell'Interno). Following the last one, ORTH surface temperatures resulting in a spectral emission which includes wavelengths less than 3 microns have to be considered, in the case of ORTHs with thermal power greater than 34.89 kW, as hazardous for exposed people. Although the ORTHs emission spectrum partially covers the near infrared region (0.8-1.4 microns) at 400 degrees Celsius and may adversely affect the retained tissue a gross evaluation of the near infrared energetic flux, weightened on the surface unit, allows to exclude this risk. On the opposite, the results of the same evaluation carried out in the medium and far infrared spectral region at 200 degrees-400 degrees Celsius (the normal temperature range for ORTHs) do not allow to preliminary exclude a thermal risk for eye structures such as lens, near the tube surface at least. In every case, a burn hazard for both corneal tissue and skin is excluded. With the aim to carry out a detailed set of radiometric estimates, some preliminary considerations are furnished concerning the risk assessment for the eye, with reference to the following parameters: emission spectrum, energetic flux, workstation, presence of reflecting surfaces, potential interferences, exposure duration, angle between the incident radiation on eye surface and the optic axis. ACGIH 1992/93 for infrared radiation TLVs are followed as reference standard.
除家庭房间外，高架辐射管加热器（ORTH）是一种有效的室内供暖系统（如仓库、工厂、汽车维修车间、造船厂、温室、学校礼堂等）。安装的设备数量不断增加，这得益于其诸多优点，如加热均匀、无空气流动、节能、多功能性和安全性。室内供暖通过红外辐射实现，红外辐射由燃烧废气在管内循环产生，并由位于管子周围的一组反射面收集。在本报告中，我们关注ORTH红外辐射的特性，以及其对暴露人群（尤其是在该系统供暖区域工作的人员）潜在的健康风险。这样做的一个原因是意大利存在一项特定法规（Circolare N. 1322/4134 - 28.01.1992，内政部民防总局）。根据该法规，对于热功率大于34.89千瓦的ORTH，其表面温度导致的光谱发射包含小于3微米波长的，必须被视为对暴露人群有害。尽管ORTH的发射光谱在400摄氏度时部分覆盖近红外区域（0.8 - 1.4微米），可能会对保留组织产生不利影响，但对近红外能量通量进行基于表面单位的粗略评估后，可以排除这种风险。相反，在200摄氏度至400摄氏度（ORTH的正常温度范围）的中红外和远红外光谱区域进行的相同评估结果表明，至少在靠近管表面的位置，不能初步排除对眼睛结构如晶状体的热风险。在任何情况下，都排除了对角膜组织和皮肤的烧伤风险。为了进行一系列详细的辐射测量估计，我们针对眼睛的风险评估提供了一些初步考虑因素，涉及以下参数：发射光谱、能量通量、工作场所、反射面的存在、潜在干扰、暴露持续时间、入射到眼睛表面的辐射与光轴之间的夹角。以美国政府工业卫生学家会议（ACGIH）1992/93年的红外辐射阈限值（TLVs）作为参考标准。
