Alcohol

Alcohol is the most commonly abused drug in the UK. It is unique in the fact that it is volatile enough to be detected on expired breath. Alcohol use can be detected and recorded in a number of ways (including the detection of past regular use via hair analysis). The most common of these is via a "breath test". In a similar way that the police may do a roadside breath test where they suspect "drink driving", we can perform an identical test on employees / persons using the same Home Office approved breathalysers.

The amount of alcohol in a drink is measured in units. To work out how many units of alcohol are in a drink, use the following equation:

ABV% (Alcohol by volume or how much "proof" a drink is) MULTIPLIED BY the amount in millilitres DIVIDED BY 1000.

For Example: A bottle of 12.5% wine contains: 12.5 x 750ml / 1000 = 11.475 units of alcohol.

The amount of units you can drink before having a Breath Alcohol Content (BrAC) or Blood Alcohol Content (BAC) over and above the UK drink drive limit, is hugely different from person to person and is affected by many variables - including: sex, height, weight, age, health, food in stomach etc etc etc.

The table below is to be used as an indication only, and in no way infers accuracy or definitive fact. ScreenSafe UK recommend the only safe drink drive level is ZERO.

Approximate blood alcohol percentage
Number of Units
Body Weight in Pounds
  100 120 140 160 180 200 220 240 "Under the influence" level
1 .04 .03 .03 .02 .02 .02 .02 .02
2 .08 .06 .05 .05 .04 .04 .03 .03 Rarely
3 .11 .09 .08 .07 .06 .06 .05 .05
4 .15 .12 .11 .09 .08 .08 .07 .06
5 .19 .16 .13 .12 .11 .09 .09 .08
6 .23 .19 .16 .14 .13 .11 .10 .09 Possibly
7 .26 .22 .19 .16 .15 .13 .12 .11
8 .30 .25 .21 .19 .17 .15 .14 .13
9 .34 .28 .24 .21 .19 .17 .15 .14
10 .38 .31 .27 .23 .21 .19 .17 .16 Definitely
Subtract .01% for every hour of drinking

A breath test is routinely performed alongside a drug test within the workplace. There are a number of solutions to testing a breath sample for alcohol. Some qualify results only (e.g. crystals changing colour in a tube when a "positive" breath sample is provided) and some quantify results (e.g. the breathalyser unit shows a reading [usually in BrAC Breath Alcohol Content]). ScreenSafe UK recommend that a quantifiable breath test is the best way to ascertain alcohol levels in a person's system.

ScreenSafe UK can train you to take a legally defensible alcohol breath test and provide you with all the equipment and paperwork that you need. As with most things in life - with breath tests/breathalysers you basically get what you pay for. We supply solutions from £ to £££'s.

Qualitative methods (like the breath test tubes, "blow in the bag", saliva wipes etc) are purely qualitative and are reliant on colour change to indicate whether a limit has been breached. These solutions are often offered with different cut-off levels - for example 0.2 BAC, 0.5 BAC, 0.8 BAC etc. These methods are disposable, one-use solutions that are ideal as an indicator or screening method only. ScreenSafe UK do not recommend that disciplinary action is taken based solely on the results of such solutions. Cost = £'s

Personal Breathalysers (like the cheaper digital "Alcometers") are usually based on semi-conductor sensors and are designed in principle for use by a single, regular user. It is assumed that the user is a willing participant, ie. they are trying to get an accurate, consistent sample to show a measurement of their own breath sample; they are not trying to "pass a test" in any way either by varying the way they blow or any other means to avoid an accurate reading. Provided the user ensures that every time they use the device they blow in the same manner, that they take the average of 3 readings (ignoring any unexpected results) and, most importantly, use the device primarily to determine the length of time that it takes them to return a zero result, then these devices can be a very useful indication of alcohol levels in breath.

With long-term use, the user will begin to know approximately what level of result to expect for a known consumption of alcohol and will also therefore be aware if/when the readings start to become unreliable. If testing someone else, the operator has no idea what to expect, as they do not know the actual alcohol consumption (and over what period of time) of the person being tested. Therefore they cannot know for sure if the device is giving an expected or false result (high or low). Semi-Conductors can be reasonably accurate around their calibration points (usually 0.03% & 0.10% BAC) but outside of these can start to vary by a greater degree.

For personal use in determining how long it takes to return a zero result, this is fine, but it can make any one-off reading less reliable. Samples are only measured based upon a set time (& sometimes minimum pressure) but the actual volume can be varied considerably should the user choose to do so. These breathalyser solutions are ideal as an indicator or screening method only. They cannot be re-calibrated (without replacing parts/sensors). ScreenSafe UK do not recommend that disciplinary action is taken based solely on the results of such breathalysers. Cost = ££'s - £££'s

Professional Breathalysers (like the Home Office Approved Drager 6510 & 6810) are specifically designed for testing other people. They measure a set volume of breath sample (usually 1.7 litres) no matter how long or hard a person blows, and are based upon an electro chemical fuel cell rather than a semi conductor sensor. The fuel cell will usually give an accurate reading throughout their entire range, and are largely resistant to substances other than alcohol. They are more consistent, and more resistant to contamination by excess alcohol (for instance by a test taken too soon after the consumption of alcohol) and also to contamination from such things as smoke particles.

In most circumstances in the UK we would always recommend the use of a UK-certified device (like the Drager 6510 / 6810) which is Home Office approved and used by many UK Police forces, however these are more expensive than those that are non Home Office approved. In some circumstances it may be sufficient to use a non Home Office approved fuel cell breathalyser. Fuel cell breathalysers can (and should) be recalibrated regularly to maintain reliability and accuracy. ScreenSafe UK recommend that disciplinary action is only taken based on the results of a Home Office approved breathalyser. Cost = £££'s - ££££'s

ScreenSafe UK also provide a specialist piece of equipment (Interlock XT) that acts as an immobilizer if a positive breath test is supplied by the driver. The Dräger Interlock XT is a breath-alcohol measuring instrument with an integrated vehicle immobilizer. After taking a breath alcohol measurement, it prohibits a driver who has consumed alcohol from starting the motor. It can easily be installed into the vehicle (fitting service available). By installing a Dräger Interlock XT, you can avoid accidents caused by alcohol consumption. Additionally, long-term changes in the drinking attitude may be an added benefit. This unit is ideal for public service vehicles and fleet vehicles.

Alcohol Leaflet
Breathalyser Leaflet
Drager 6510 Leaflet
Drager 6810 Leaflet

The following pages may be of interest to you:

Please do not hesitate to contact Customer Services on 08450 505590 or via email (enquiries@screensafeuk.co.uk) if you require any further help or assistance.