Test method for in-situ measurement of penetration by chemical substances of chemical gloves

Status:

completed 09/2005

Aims:

Chemical protective gloves are personal protective equipment (PPE), worn in order to protect the hands and skin at the workplace during contact with aggressive chemical substances. In contrast to equipment for respiratory protection, in which penetration of the gas filter by chemicals can be detected by taste or smell, penetration by chemical substances of the glove material (elastomers) is detectable by the wearer of the glove only in exceptional cases.

This project was to develop a method, suitable for application in the field, for in-situ breakthrough measurement by chemicals of chemical protective gloves at the workplace. Consideration was given to the case-specific underlying conditions of employees concerning the use of protective gloves with regard to the particular working procedures concerned.

The measurements were conducted on the test subject under the glove, in order to give consideration to all factors which may influence permeation by chemicals during wearing of the glove.

The objective of the project was to develop a suitable and validated measurement and test method.

Activities/Methods:

Based upon comprehensive literature surveys and existing test methods, a glove test arrangement employing a model hand was first set up in the laboratory in order to permit trials of a range of methods for sampling and measurement of volatile chemicals following breakthrough by them of a glove. The objective here was to identify the detection method best suited to selective and adequately sensitive measurement of chemicals which are frequently used at workplaces and are harmful to the skin, for example hydrocarbons, solvents, and cleaning agents.

Two different methods were initially considered. In the first, a number of direct-reading gas detection instruments for continuous measurement (PID, semiconductor sensors, etc.) were tested with sampling (suction) from the void between the glove and the surface of the model hand. In the second, discontinuous-mode enrichment systems such as activated carbon pads and detector tubes placed between skin and the glove were employed.

Results:

Preliminary tests were performed in order to determine the penetration times and time/concentration characteristics of chemical protective gloves manufactured from nitrile, latex and PVC, in conjunction with solvents frequently encountered in practice (alcohols, ketones, aromatic hydrocarbons).

For the purpose of development and optimization of the in-situ method for penetration measurement on gloves during the performance of tasks at selected workplaces, the combination of nitrile glove material with a thickness of 0.1 to 0.2 mm and ethyl alcohol/acetone proved to be the most suitable test system, with penetration times of below 30 minutes.

For the purpose of penetration detection, discontinuous substance enrichment processes involving adsorbing agents (e.g. activated charcoal) were employed as passive collectors located between the skin and the glove. Portable, direct reading concentration meters (e.g. photoionization detectors) equipped with data loggers were also employed by which sampling air can be exhausted from the gap under the glove. The option of an instrument worn by the employee, which should hinder him or her only minimally during performance of the task, was optimized for both methods; close attention was paid not only to the accuracy/reproducibility of the penetration measurement, but also and in particular to the system's practicality and ease of use.

The direct reading method involving a photoionization detector (PID) with its own source of power and an integral sampling pump proved to be the more suitable, owing to the near-instant detection of penetration and the facility for display of concentration characteristics as a function of wetting of the glove by the chemical.

Initial applications of the direct reading measurement arrangement in simulated work tasks have shown it to correlate with the standardized permeation test for glove materials to EN 374-3, "Protective gloves against chemicals and micro-organisms - Part 3: Determination of resistance to permeation by chemicals".

A follow-up project which is intended to employ a range of glove types and selected work processes is in preparation.

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