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Module 6: Classifying and rating hazardous substances for the HFSP

What,why and how?|Purpose of classification systems for hazardous substances|The United Nations classification system|HSNO classification system|Rating hazardous substances for the HFSP

What,why and how?

What

  • purpose of hazardous substance classification systems
  • overview of existing systems to classify hazardous substances
  • how to use classification systems to rate hazardous substances for the HFSP

Why

  • to understand the background to classifying hazardous substances
  • to see how existing classification systems have been simplified for the HFSP
  • learn how to rate a hazardous substance for the HFSP

How

  • presentation
  • exercise and report in

When a thing ceases to be a subject of controversy, it ceases to be thing of interest

William Hazlitt

 

Exercises

  1. List two or three hazardous substances you can think of
  2. Note down the hazardous properties you think these substances have
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Purpose of classification systems for hazardous substances

Why do we need hazardous substances classification systems?

Hazardous substances present a wide range of risks to human health and safety, the natural environment and infrastructures, depending on their inherent properties. Hazardous substance properties include:

  • explosive
  • flammable
  • corrosive
  • oxidising
  • radioactive
  • infectious
  • toxic
  • ecotoxic

One of the purposes of the HFSP is to recognise the hazards different hazardous substances present on a site so that their risks can be assessed within the context of their location and the surrounding environment.

Any substance may have one or more hazardous properties and the HFSP considers all properties a substance exhibits.

Depending on the type and degree of their hazardous properties, hazardous substances require different levels of control in their use, transportation, storage, and disposal to manage their risks appropriately.

Classification systems for hazardous substances enable:

  • hazardous substances to be clearly identified
  • specific hazardous properties to be assigned to different hazardous substances
  • appropriate controls to be applied to specific hazardous substances

What classification systems are there?

There are two principal classification systems for hazardous substances that are important in the New Zealand context. These are:

  • the United Nations (UN) Classification System
  • the classification system adopted under the HSNO Act

In order to rate hazardous substances for the HFSP, we rely mainly on the classification of the HSNO Act.This is based to a large degree, on the UN Classification System, but goes further in some areas. Both classification systems are discussed in greater detail below.

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The United Nations classification system

In worldwide trade, hazardous substances in either raw or processed form are transported daily between facilities, regions, and continents. The United Nations Classification System (United Nations Recommendations on the Transportation of Dangerous Goods or UNRTDG 1998, Eleventh Revised Edition) is a classification system which has been designed to control the risk of hazardous substances in transport.

The UN Classification System is the most widely used system in the world for the transport of dangerous goods by land, air, and sea. Associated with this system are:

  • nine dangerous goods classes and associated packaging groups
  • a numbering and identification system for dangerous goods
  • a marking system for packages, vehicles, and containers based on a range of characteristic diamond labels
  • a range of controls for packaging, bulk transport, and the stowage and compatibility of hazardous substances (these may vary for transport by land, air, and sea)

The nine UN dangerous goods classes and associated Packaging Groups are listed in Table 6.1.The UN Classification System is based on a prioritisation system which assigns controls for the primary and one subsidiary risk of the substance.

Therefore, under the UN classification system, only the most significant hazards of a substance in relation to transport are considered. Further, because of the inherent risks associated with transport, the UN Classification System focuses on reactive substances and to a lesser degree on toxic and ecotoxic substances.

Table 6.1 United Nations Dangerous Goods Classes
UN Class Description
Class 1 Explosives
Class 2 Gases
Class 3 Flammable liquids
Class 4 Flammable solids
Class 5 Oxidising substances
Class 6 Poisonous and infectious substances
Class 7 Radio-active substances
Class 8 Corrosive substances
Class 9 Miscellaneous dangerous substances
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HSNO classification system

Overview

As part of its control framework for hazardous substances, the HSNO Act sets out a range of requirements for the control of hazardous substances. Among these are the Hazardous Property Performance and Pan-Life Cycle Performance Controls.

For the purpose of these controls, hazardous substances are grouped into the following major hazardous properties:

  • explosive
  • flammable
  • oxidising
  • corrosive
  • toxic
  • ecotoxic
  • the capacity to evolve another substance with any of these properties upon contact with air or water

Note: the HSNO Act does not deal with radioactive or infectious substances, as these are dealt with by other legislation. By implication, the HFSP also does not deal with these hazardous properties.

Hazardous Substances Control Matrix

The hazardous properties covered by the HSNO Act form the basis for the “Hazard Control Matrix” (Tables 6.2 and 6.3). This matrix is, to a significant degree, based on the UN classification system for hazardous substances.

However, the Hazard Control Matrix is considerably more comprehensive compared to the UN classification system, because it is designed to cover all aspects of hazardous substance control and management throughout the substance’s life-cycle, and addressing all the hazardous properties of a substance.

The matrix covers additional hazardous properties where:

  • the UN Classification System is inadequate (especially for toxic and ecotoxic properties
  • the hazard level of a particular substance is lower than the lowest UN classification level but is still considered to be significant in terms of potential effects
  • the hazard level is so high that transport of the substance is not permitted.

Overall, the HSNO Hazard Control Matrix aims to cover all conceivable hazardous substance properties and to assist managing the risks of hazardous substances over their entire life cycle. Specific performance standards apply to each hazard type and level of the Hazardous Substances Control Matrix, depending on hazardous properties and life-cycle considerations.

Table 6.2 Physical hazard classification

See Table 6.2 at its full size

Table 6.3 Biological hazard classification

See Table 6.3 at its full size

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Rating hazardous substances for the HFSP

Why we need to rate hazardous substances for the HFSP

The rating of hazardous substances has to be carried out before any HFSP calculations can be commenced. It is necessary because:

  • we need to understand all possible hazard properties of the hazardous substances we assess
  • once we have classified a substance, we are able to determine its Hazard Level for any of the three Effect Types
  • based on the Hazard Levels, we can assign Base Quantities for each substance under the three Effect Types
  • once we have determined the relevant Base Quantities for a hazardous substance(s), we can start with the HFSP calculations.

What we need to do

The hazardous classification system adopted for the HFSP is largely based on the HSNO Control Matrix – however with a primary purpose of simplifying this for assessment purposes.

As mentioned earlier in Module 3, the HFSP rating system is used to assess each substance in terms of the three Effect Types and three Hazard Levels which have been identified for the HFSP, as follows:

  • Fire/Explosion Effect Type
  • Human Health Effect Type
  • Environment Effect Type

Each of the above Effect Types is divided into three Hazard Levels:

  • High
  • Medium
  • Low

The hazardous substances classification system used by the HFSP gives equal weighting to all hazardous substance properties. This is consistent with the approach taken by the HSNO Act. This means that every substance is equally assessed in terms of all potential hazardous properties.

Why and when users of the HFSP need to rate hazardous substances

The HFSP hazardous substances classification system is contained in Appendix A of the Red Book, together with applicable Hazard Ratings in each Effect Type.

Overall, once the HSNO classification is known for a substance, it is very easy to rate this substance for the HFSP, based on the guidance provided in Appendix A of the Red Book. Table 3.1 in Module 3 summarises Appendix A even further, and provides a Base Quantity for every hazardous substance class.

However, as discussed in Module 2, the classification of “legally existing” hazardous substances under the transitional provisions of the HSNO Act will take some time to complete. This applies in particular to the “NOTs” (hazardous substances not yet assessed under the repealed Toxic Substances legislation) which may take several years to classify.

In the meantime, users of the HFSP may need to rate hazardous substances for the HFSP on their own, using both the HSNO and the UN Classification systems. In many cases, this can be quite an involved exercise requiring research of Material Safety Data Sheets (MSDSs) and specialist hazardous substances databases.

Guidance for rating hazardous substances

The Ministry for the Environment has developed a Rating Guide to assist users with rating hazardous substances for the HFSP while the HSNO Act is in its transitional phase. This Rating Guide is contained in Appendix C of the Red book.

Exercise 6.1

a) Review Appendix A of the Red Book which is the basis for converting the HSNO classification into HFSP Ratings

  • what is the HFSP Rating for HSNO Class 3.2A?
  • what is the HFSP Rating for HSNO Class 4.1.3A

b) Using Table 3.1 in Module 3:

  • indicate the Base Quantity for HSNO Class 1.1
  • indicate the Base Quantity for HSNO Class 9.1B

c) Review the HFSP Rating Guide in Appendix C of the Red Book and associated Evaluation Chart, and follow through the example of chlorpyrifos. Check the Table at the back for the information requirements.

  • how confident are you about rating a hazardous substance of your own?
  • what information sources would you access?
  • what can you do if relevant information is not available?

Key application

Identify a key application of the information you’ve learnt in your day-to-day working environment.

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