Standards Development

Scope

This International Standard describes the procedure for the preparation of test panels from refractory materials by gunning through pneumatic nozzle mixing type guns at ambient temperatures. The test pieces are for the determination of properties on as-gunned products prepared under either “standard conditions” (as required for quality assurance or product development) or “site conditions”. In the case of “site conditions”, the purpose of the testing is to establish the properties pertaining to a given installation or a given set of installation conditions. In this case, the panel is obtained during the on-site installation. Such parameters as ambient temperature, gunning elevation, air pressure and curing conditions (temperature, orientation of the panel) applying during the preparation of the panel are as near as possible to the same parameters pertaining to the site installation. This International Standard does not apply to plastic gunning mixes and might not apply to those mixes that contain aggregates that are susceptible to hydration.

It also does not apply to shotcrete type mixes. (These are dealt with in ISO 18886, “Refractory testpiece preparation – Gunning refractory panels by wet gunning techniques.”).

Purpose

Monolithic refractories have for several years now increased in market share over pressed, shaped refractories. One method for installing monolithic refractories is through gunning – either wet or pneumatic. A wet gunning standard has been developed in more recent times – refer to ISO 18886: Refractory test-piece preparation -- Gunning refractory panels by wet gunning techniques. However it has been several years since ISO 20182 has been formerly reviewed.

The current standard has several features that do not align with current industry practice.

These include:

1) The current standard refers to predampening but with gunning grade cements now available this practice is rarely required.

2) The hose diameters referred to in the current method appear to be too small for current industry practice.

3) Support plates options do not have sufficient edge containment

4) The scope should be changed to allow for laboratory and site prepared samples as per ISO 18886.

5) No guidance on the gunning of materials containing stainless steel fibre.

Preparation of test pieces for evaluation is important in the refractory industry and consumers of refractories, to ensure the correct quality of installation through installer evaluation and training and material quality checks and also to allow development of materials that have a longer service life and hence decrease the refractory consumption for a given amount of industrial output.