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A Total Fractional Value, or TFV, is the concentration of a hazardous ingredient divided by the hazard limit of that hazard for that ingredient. They can appear pretty confusing when you first look at them. We’ll explain this in more detail in this guidance document.

Why are TFVs useful?

TFVs are useful because they show where a hazard (generally a Risk phrase) becomes applicable to a formulation.

To discuss TFVs, it is useful to do a quick run through some other aspects of the legislation.

In the EC Dangerous Preparations Directive, the “conventional method” of determining hazards for a formulation is to take the ingredients, their percentages and their hazards and perform some calculations to determine the overall hazards of the formulation.

The effects of “cumulative” hazards, e.g. environmental, corrosive and irritant hazards, add together across all of the ingredients with the same hazard. For “non-cumulative” hazards, e.g. sensitising, the hazards do not add together, so only the ingredient with the highest hazard contribution counts towards the hazard of the formulation.

A formulation carries a specific hazard if the sum (for cumulative hazards), or maximum (for non-cumulative hazards) of the TFVs of the ingredients for the hazards is one or more.

Concentration Limits

The legislation specifies “General Concentration Limits” – standard Concentration Limits for different types of hazard which are applicable for most ingredients. However, for some chemicals, different Concentration Limits – “Specific Concentration Limits” – must be used. An example is Cedrene Alpha, found in Cedarwood oil, which has Specific Concentration Limits for environmental hazards which are ten times lower than the General Concentration Limits for those hazards.

The combination of cumulative hazards and Specific Concentration Limits can make it very difficult to calculate formulation hazards manually – just one reason why good software is important!

Here is an example from the DPD legislation:
2. The following preparations shall be classified as toxic:
2.1. owing to their acute lethal effects and assigned the symbol .T., the indication of danger .toxic. and the risk phrases R23, R24 or R25;
2.1.1. preparations containing one or more substances classified as very toxic or toxic that produce such effects in individual concentrations equal to or greater than:
(a) either the concentration specified in Annex I to Directive 67/548/EEC for the substance or substances under consideration, or
(b) the concentration specified at point 1 in Part B of this Annex (Table I and I A) where the substance or substances do not appear in Annex I to Directive 67/548/EEC or appear in it without concentration limits;
2.1.2. preparations containing more than one substance classified as very toxic or toxic in lower individual concentrations than the limits specified under 2.1.1(a) or (b) if:

where:
PT+ = is the percentage by weight or by volume of each very toxic substance in the preparation,
PT = is the percentage by weight or by volume of each toxic substance in the preparation,
LT = is the respective toxic limit specified for each very toxic or toxic substance, expressed as a percentage by weight or by volume;

Another tricky concept is that of Lower Limits of Concentration.  In essence, when totalling the TFVs for a cumulative hazard, you must only consider ingredients present at a concentration at or above a specified limit for the particular hazard – the “Lower Limit of Concentration” – ignore ingredients with a lower concentration.  Click here for more information about Lower Limits of Concentration

Simple example of calculating a TFV

Imagine you have several ingredients in a formulation classified as R36 – Irritating to eyes.  R36 is a cumulative hazard.  Altogether there are 15% of R36 ingredients. 

Should the formulation be classed as R36?

We look at the General Concentration Limit in the legislation to find out.  For R36, the General Concentration Limit is 20%, that is, if 20% or more of a formulation’s ingredients are classified as R36, and none of those ingredients have Specific Concentration Limits, then the formulation will be classified as R36.  So in this case, where we have 15% of R36 ingredients, the formulation is not classified as R36.

Where do TFVs come in?

In the above R36 example, there were 15% R36 ingredients and the General Concentration Limit for R36 labelling is 20%.  This can be expressed as a TFV in the following way:

TFV = Concentration / General Concentration Limit, so   
TFV = 15/20 = 0.75

For other types of hazard the General Concentration Limits are different.  R43 is a non-cumulative hazard with a General Concentration Limit of 1%.  So if any individual ingredient classified as R43 is present at 1% or above, the whole formulation must be classified as R43.  For a formulation with 0.8% of an R43 ingredient, the TFV can be expressed as follows:

TFV = Concentration / General Concentration Limit, so
TFV = 0.8/1 = 0.8

TFVs are useful because you can look at complex formulations with different hazards which may have different General Concentration Limits and understand where any formulation hazards are coming from. By using Formpak Analysis Reports you can see which ingredients are contributing to which hazards.

In the following example, a formulation contains 25% ingredients classed R36 and 1.5% of a single ingredient classified R43.
TFV = Concentration / Default Limit   
For R36   TFV = 25/20 = 1.25
For R43   TFV =1.5/1 = 1.5
Here, the formulation would be classified both R36 and R43.
Please note that TFVs can get more complicated when there are Specific Concentration Limits and where there are cumulative hazards.
Also note that TFV < 1 for all the hazards of a formulation does not necessarily mean that the formulation requires no hazard labelling. For example, sensitising ingredients may have to be declared on the label at low concentrations.