Testing gloves for protection against pesticides

Describing permeation testing of pesticides by EN ISO 19918:2017+A1:2021 in accordance with the requirements of ISO 18889:2019.

Permeation testing against chemicals with low vapour pressures is conducted by EN ISO 19918:2017+A1:2021, which is used to demonstrate compliance with the cumulative permeation requirements in ISO 18889:2019 – ‘Protective gloves for pesticide operators and re-entry workers – Performance requirements’.

ISO 18889:2019

ISO 18889:2019 is the requirement standard for gloves protecting against pesticides. There are three glove types classified by this requirement standard: ‘G1’, ‘G2’ and ‘GR’. G2 gloves offer the highest level of protection and GR types offer only partial protection. There are numerous performance requirements for each glove type, which vary depending on the end use of the gloves.

Within ISO 18889, definitions are provided for each glove type and for their intended use. For G1 gloves, it would be anticipated that these gloves would be used by workers who may be spraying crops with pesticide chemicals. These gloves would not suitable for use with concentrated pesticide formulations or in scenarios where mechanical risks exist. In contrast, G2 gloves are the only type that are suitable for use with concentrated pesticide solutions. It could therefore be inferred that these gloves would be suitable for wear during the preparation of pesticide solutions for use on crops and for activities where mechanical risks exists.

As previously mentioned, GR gloves offer only partial protection from pesticides. There is a defined minimum coated area which provides protection from pesticides, this being on the palm and fingertips (see figure 1). This type of glove would not be suitable when the wearer comes into direct contact with pesticide solutions, and so would be more suitable for use where only contact with pesticide residues may occur – such as in the picking of crops. It is noted within the standard that GR gloves are not suitable for use by pesticide operators. It can be inferred that G2 offers the highest level of protection. Therefore, any glove that meets the requirements for G2 would also meet the requirements for a G1 glove.

Key definitions contained within ISO 18889
Pesticide	Substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest or weeds.
Pesticide operator	Person handling pesticides in, for example, agricultural settings, green spaces or roadsides. Note: ‘Handling’ includes tasks such as mixing, loading, transferring or applying pesticides, as well as cleaning, adjusting or repairing the parts of mixing/loading/application equipment that may contain pesticide residues, assisting with the application of pesticides, and disposing of pesticides or pesticide containers.
Re-entry worker	Person who can be in contact with a partially or fully dried pesticide product, as part of their work/employment, in an area that has previously been treated with pesticides.

Other testing requirements

Within ISO 18889, there are several performance requirements in addition to the pesticide permeation testing which must be fulfilled. These are outlined in table 1. Clause 4.1 lists ISO 21420 – ‘General requirements and test methods’, which applies to all protective gloves. This includes testing for sizing, dexterity and chemical innocuousness. Under Clause 4.2.1, penetration requirements are outlined. This includes air leak and water leak from ISO 374-2 (please note that this is only applicable for types G1 and GR).

Table 1: Testing requirements for G1, G2 and GR gloves
Clause	Requirement	Standard	Requirements
			G1	G2	GR
4.1	General requirements	ISO 21420	Fulfilled	Fulfilled	Fulfilled
4.2.1	Penetration	EN 374-2, Clauses 7.2 and 7.3	Pass	Pass	N/A
4.2.2.1	Permeation	ISO 374-1	≥Type C	≥Type B	≥Level 2 with chemical K
4.2.2.2	Permeation	ISO 19918	≤10 µg/cm2	≤1 µg/cm2	≤1 µg/cm2
4.2.3.1	Length	ISO 18889	Fulfilled	Fulfilled	N/A
4.2.3.2	Coated area	ISO 18889	N/A	N/A	Fulfilled
4.2.4	Mechanical requirements	ISO 23388 Clause 6.1		≥ Level 2	≥ Level 2
		ISO 23388 Clause 6.2		≥ Level 1 or: ≥ Level A	≥ Level 1 or: ≥ Level A
		ISO 23388 Clause 6.3
		ISO 23388 Clause 6.4		N/A	≥ Level 1
		ISO 23388 Clause 6.5		≥ Level 1	≥ Level 1

Permeation requirements are listed under Clause 4.2.2.1 of ISO 374-1, and the harshest of these requirements apply to G2 gloves. The minimum requirement is ‘Type B’, which means that the gloves have achieved a minimum of a ‘performance level 2’ against three chemicals listed in ISO 374-1. G1 requires a Type C and GR gives a specific level against a specific chemical, rather than one of the usual defined glove types under ISO 374-1 (performance level 2 against chemical ‘K’, 40 per cent sodium hydroxide). These requirements are to ensure that G1 and G2 gloves have a minimum resistance to chemicals before assessing them for protection against pesticides.

Minimum length requirements are outlined in Clause 4.2.3.1. This defines a minimum glove length of 290 mm for a G2 glove and a minimum of 240 mm for a G1 glove. An important note within this clause is that ‘For G1 glove with a glove length between 240 mm and 290 mm, a caution sentence shall be included in the user instruction to check the minimum overlap'. If the overlap between the glove and the sleeve of the garment worn by the pesticide operator or re-entry worker is less than approximately 50 mm, a glove with a longer length should be used. Clause 4.2.3.2 defines the minimum coated area of a GR glove (see figure 1).

Clause 4.2.4 outlines the mechanical protection requirements that are applicable to G2 and GR gloves. ISO 23388 requirements are listed from Clause 6.1 to 6.5 (abrasion, circular blade cut, straight blade cut (ISO 13997), tear and puncture resistance). Each of these is applicable to both types G2 and GR, excluding ISO 23388 Clause 6.4 (tear resistance), which is applicable to GR gloves only. The minimum level of protection required for each of these clauses is generally the lowest (Level 1 or ‘A’ for straight blade cut) for each test clause, excluding Clause 6.1 abrasion resistance which requires a minimum Level 2.

The requirements given in ISO 18889 are all refenced by ISO standard. However, EN ISO standards (such as EN 388 in place of ISO 23388) would be sufficient for certification purposes.

Test method for resistance against pesticide chemicals

EN ISO 19918:2017+A1:2021 is the method for measuring cumulative permeation of chemicals with low vapour pressures. This is the method used for showing compliance to ISO 18889:2019. The pesticide surrogate test chemical ‘EC-DY’ is defined within the ISO 18889 requirement standard. This is a solution containing Disperse Yellow 26 that is used to represent the behaviour of a pesticide chemical. As defined in the standard, testing can be conducted with either the diluted (2.5 per cent EC-DY) or concentrated surrogate solution.

EN ISO 19918 is a method designed to measure cumulative permeation only – that is, the amount of permeated chemical per squared centimetre of the glove. The time at which the permeation reaches a specified rate cannot be measured by this method (neither can resistance to penetration or degradation). If requested, other pesticides that may be more applicable to the end use of the glove can be tested using this method and the same pass criteria would apply as for EC-DY. This would need to be conducted as well as testing against EC-DY, as this surrogate solution is a requirement of the ISO 18889 standard.

Testing is completed in a horizontal, cylindrical cell with the glove sample horizontal within the cell and the challenge chemical (in this case a pesticide surrogate solution) applied on top of the glove specimen (see figures 2 and 3). A collector disc (which is an absorbent material that acts as a collection medium) is located below the glove specimen.

After the defined 60-minute test duration, the cell is deconstructed (15 minutes is the test time against the concentrated surrogate solution). The collector disc is removed and extracted in methanol (other extraction solvents may be used for different challenge chemicals). The test with this extracted solution is then run on a suitable analytical instrument, such as LC-MS/MS.

The concentration of the pesticide surrogate that has permeated through the glove material and has been collected on the collector disc is then calculated, and a cumulative breakthrough is determined in µg/cm². If this cumulative permeation level is below what is required for the glove type being claimed, the glove will achieve a ‘pass’ result.

To achieve a pass result for a G1 glove, the requirement is a maximum of 10 μg/cm² cumulative permeation for all specimens when tested against the diluted surrogate. For a G2 glove, the maximum cumulative permeation is 1 μg/cm² for all specimens when tested against both the diluted and concentrate surrogate. For GR gloves, the maximum cumulative permeation is 1 μg/cm² for all specimens when tested against the diluted surrogate only.

The testing is conducted in triplicate and the total cumulative permeation of each of the three triplicates must be within 20 per cent of the mean permeation amount. If this is not the case and the results are too variable, the test must be repeated again in triplicate. If the three successive exposures are still not within the defined range, the gloves will be deemed to be ‘inhomogeneous’ and a pass result cannot be assigned.

For any G1 or G2 gloves that are longer than or equal to 400 mm in length, the permeation test will be required to be tested on both the palm and cuff of the gloves, and both areas must meet the specified requirements.

Marking

Marking requirements of protective gloves for pesticide operators and re-entry workers are outlined in Clause 6 of ISO 18889. This states that marking shall be conducted in accordance with the marking requirements for protective gloves of EN ISO 21420 and with the requirements within ISO 18889. It is specified in this clause that the glove type (meaning G1, G2 or GR) is noted below the pictogram to help the user identify the most applicable glove for their use (shown in figure 4).

Within Clause 6, it is also stipulated that for a G1 glove with a glove length between 240 mm and 290 mm, a caution sentence shall be included in the user instruction to check the minimum overlap between the glove and the sleeve of the garment worn by the pesticide operator or re-entry worker. If the overlap is less than approximately 50 mm between the glove and the sleeve, a glove with longer length should be used. There is also a requirement to specify if the gloves are for single use only. If the gloves are for repeated use, the ‘decontamination instructions’ should be included.

Clause 7 of ISO 18889 outlines the requirements for information to be supplied by the manufacturer. In this clause, there are 11 warnings that need to be included in the user instructions, seven of which are mandatory and four that should be included if relevant. These warnings include information on decontamination, inspections prior to use and information for use of gloves of a non-homogeneous design.

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