Resistance to permeation by chemicals防化学物质渗透测试
What is permeation?什么是渗透？
The process by which a chemical move through a physical barrier (it can be a textile or a polymer material for example) on a molecular level.
化学物质在分子水平上穿过物理屏障（可以是纺织品或聚合物材料）的过程。
Majorly 3 physico-chemical phenomena are involved in permeation:
· Sorption of liquid molecules on the contact surface of the material
· Diffusion of the absorbed molecules in the material
· Desorption of the molecules on the opposite surface of the material
渗透主要涉及3种物理化学现象：
· 液体分子吸附在材料接触面上
· 吸附分子在材料中的扩散
· 材料另一面上分子的解吸
Schematic permeation phenomenon
渗透现象示意图
This process is a distinctly different mechanism than penetration where chemicals move through voids in materials without change of state.
这个过程是一种和穿透截然不同的机制，穿透是化学物质在不改变物质状态的情况下穿过材料中的空隙。
How to measure permeation?如何测量渗透率？
The protective property of a material against permeation by a chemical is determined by measuring the rate of permeation through the test material. Using a special testing cell, the material is exposed to a chemical in liquid or gaseous form, the mass of chemicals that has permeated through is determined analytically over a 480 min period.材料对化学物质渗透的保护性能是利用测量通过测试材料的渗透率来确定的。使用特殊的测试装置，将材料暴露于液态或气态的化学物质中，在 480 分钟内分析确定已渗透的化学物质的质量。
Schematic of a common permeation rate graph
常规渗透速率示意图
What are permeation levels?什么是渗透水平?Depending on the material properties, the chemical permeates through at different pace. This is the base for the comparison of materials. For this purpose, the European standard EN 16523-1:2015 + A1:2018 defines a standard permeation rate (or normalized permeation rate “NPR”) arbitrary fixed at 1.0 µgNaN-2.min-1. 根据材料的特性，化学物质会以不同的速度进行渗透。这是材料对比的基础。为此，欧洲标准EN 16523-1:2015+A1:2018规定了标准渗透率（或标准化渗透率“NPR”），固定为1.0µgNaN-2.min-1。
With this reference value, manufacturers can compare different material’s performance by measuring the elapsed time between initial contact of the chemical with the outside surface of the material and the time at which the chemical is detected on the other side of the material at a permeation rate of 1.0 µgNaN-2.min-1. This information obtained on material is the material’s Normalized Breakthrough Time (“NBT”)*. 有了这个参考值，制造商可以通过测量化学物质与材料外表面的初始接触时间与在材料另一侧以1.0µgNaN-2.min-1的渗透速率检测到化学物质的时间之间的经过时间来比较不同材料的性能。此信息即为材料的标准化穿透时间（“NBT”）* 。
The standard EN ISO 374-1: 2017 that defines the performance requirements for chemical resistant gloves gives the performance level classification table according to the materials’ NBT:防化学手套性能要求的标准 EN ISO 374-1:2017 根据材料的 NBT 给出了性能等级分类表：
The permeation performance level is the criteria used for the classification, the CE certification, and the marking of the PPE.
渗透性能水平是个人防护用品的分类、CE 认证和标记的标准。
* For safety reasons, it is important to keep in mind that chemical permeation is a gradual and continuous process over time and that the NBT does not correspond to the moment when the chemical permeates first the material. NBT measurement serves only the purpose of comparing materials’ performance.
* 出于安全考虑，请务必注意，化学渗透是一个逐渐和持续的过程，NBT并不是化学物质首先渗透到材料的时刻。NBT测量仅用于比较材料的性能。
Evaluate your PPE permeation level with
PPE产品的渗透性能
CTC laboratories accredited in France by COFRAC, and in Hong Kong by HOKLAS have developed and enhance its capacity for measuring permeation rates in PPE (gloves, garments) for those chemicals defined by permeation standards EN ISO 374-1: 2017 (see below table).已获得法国 COFRAC 认证和香港 HOKLAS 认证的 CTC 实验室增强了其测量 PPE（手套、服装）渗透率的能力，欢迎参考下表中列出的EN ISO 374-1: 2017渗透标准 。
Among the many requirements set out by the PPE test standards, particular attention must be paid to those required for defining the instructions for use in particular, the information which gives the possibilities of use (single use or reusable) or the PPE maintenance and washing recommendations.
在 PPE 测试标准的众多要求中，必须特别注意产品介绍说明，特别是使用说明（一次性或可重复使用）、PPE 维护和清洗建议 。
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