A transport supervisor in Bhiwandi has a printed slip on the desk. It reads 0.021. The driver says he had cough syrup at breakfast and that a small number like that is "within the normal range". The dispatcher wants the vehicle out. Loading is done. The customer is waiting in Nashik.
That is the moment when the phrase alcohol breath test normal range stops being a search query and becomes a decision. And the answer is not comforting to anyone hoping for a grey zone: on a breath alcohol screening test, the normal range is zero. There is no band of acceptable positivity built into the human body. If a properly operated analyser reports alcohol, alcohol is what it found.
Whoever releases that vehicle carries the consequence. Not the dispatcher who was in a hurry, and not the driver who quoted a number he did not understand.
The short answer: the normal range is 0.000
Ethanol is not a substance the body maintains at a baseline level. Unlike glucose or haemoglobin, there is no physiological reference interval to sit inside. A sober person blowing into a working fuel-cell analyser produces 0.00.
So when a lab report or a medical site shows "reference range: negative" or "< 10 mg/dL", that is not permission to be slightly positive. It is the detection floor of the method, not a healthy range.
The confusion comes from mixing two different frameworks:
• Clinical reference ranges, which describe what is usual in a healthy population.
• Legal and policy thresholds, which describe the point at which the law or your own rules take action.
Breath screening lives entirely in the second world. This is a distinction worth understanding before you write a policy, and it is covered further in Alcohol and Blood Test: What the Lab Measures and What Breath Screening Already Answers.
The number that matters on Indian roads
Section 185 of the Motor Vehicles Act, 1988 sets the driving threshold at 30 mg of alcohol per 100 ml of blood, detected by a breath analyser. Expressed as a percentage, that is 0.03% BAC.
That is a prosecution threshold, not a safety threshold. Judgement, reaction time and risk-taking start shifting well below it. An employer who sets 0.029 as "acceptable" has adopted the law's floor as a ceiling and will struggle to explain that choice after an incident. The employer's wider exposure is set out in Driving Under the Influence of Alcohol: The Law, the Test and the Employer's Exposure.
Several Indian safety regimes are stricter still. Aviation and railway operating rules work on a nil-reading basis for safety-critical staff, and most mines, refineries, ports and chemical plants apply the same logic in their internal policies: any detectable alcohol removes the person from the task.
Units: the same reading in four different forms
Much of the argument about "normal" is really an argument about units. The same breath sample can be reported four ways.
Unit What it means Roughly equivalent to 0.03% BAC
% BAC (g/100 ml blood) Percentage by volume in blood 0.03%
mg/100 ml blood Indian legal wording 30 mg/100 ml
mg/L breath (BrAC) What the sensor actually measures about 0.15 mg/L
g/210 L breath Common on imported displays about 0.03 g/210 L
Breath analysers measure breath and convert to a blood-equivalent figure using a fixed ratio. So a device reading 0.15 mg/L and a device reading 0.03% are saying the same thing in different languages.
Before you argue with a result, confirm which unit the display is set to. A reading of 0.15 looks alarming in % and is a legal borderline in mg/L. Getting this wrong in a warning letter is how good cases fall apart. The relationship between breath and blood measurement is compared in detail in Blood Alcohol Content Tester: What It Measures and Which One Your Site Needs.
What the bands actually indicate
These are widely used interpretive bands, not thresholds you should build a policy around. They exist to answer the question, "is this number small?"
Reading (% BAC) What is typically observed
0.00 No alcohol detected. The only genuinely normal result
0.01 – 0.03 Below the Indian driving threshold, but detectable. Mild loosening of judgement
0.03 – 0.05 At or above the legal driving limit. Reaction time measurably slower
0.05 – 0.10 Impaired coordination, speech and attention
0.10 – 0.20 Clear intoxication, unsafe near any machine or vehicle
Above 0.20 Medical concern as much as a disciplinary one
For a workplace, the useful cut is much simpler: zero, or not zero.
How long alcohol stays detectable on the breath
The body eliminates alcohol at a fairly steady rate, roughly 0.01% to 0.02% BAC per hour for most adults. Nothing meaningfully speeds it up.
That arithmetic is what makes night-shift and early-shift screening non-negotiable. Someone who reaches a high level near midnight can still register a positive reading at six in the morning. The person feels fine, has slept, and is genuinely surprised by the display. The sensor is not.
As a working rule for policy discussions: a heavy evening can remain detectable into the next morning, and "I stopped drinking hours ago" is not a defence a supervisor can accept on assertion alone.
Why a tiny reading is not automatically a discipline case
This is where a good procedure protects both sides. Very low readings have three common explanations:
• Mouth alcohol. Mouthwash, breath freshener, some cough syrups and certain ayurvedic tonics leave ethanol in the mouth. It clears in about 15 to 20 minutes.
• Sampling too soon after eating, smoking or vomiting, which can disturb the sample.
• Genuine residual alcohol from the previous night.
The fix is procedural, not technological. Wait 15 minutes with water only, then retest. If the second reading is zero, it was mouth alcohol. If it is the same or higher, it is systemic. A device with a mouth-alcohol flag makes this faster, but the waiting period matters more than the feature.
Record both readings. The full sequence for a result that survives challenge is laid out in The BAC Test That Holds Up: Procedure, Records and Defending a Result.
How to read alcohol test results on your own device
Four things to check on every result, in order:
• The unit on the display or printout.
• The mode. Passive or non-contact sniffing gives an indication only. Only an active test through a mouthpiece produces a number you can act on.
• The value against your policy threshold, not against the legal driving limit, unless the two are the same by design.
• The record. Date, time, device serial, operator name, both readings if a retest was done.
A screening result is a decision trigger, not a verdict. If someone contests it, the escalation path is a confirmatory test at a hospital or authorised centre. What that adds and what it does not is explained in Blood Alcohol Tester vs Breath Analyser: What a Safety Manager Actually Needs.
Setting the number in your policy
Write the threshold down before you need it. A policy that leaves "normal" to the supervisor's judgement transfers the entire risk to that supervisor.
Most Indian operations end up in one of two positions:
• Zero tolerance (0.00): any detectable alcohol means removal from duty. Standard for driving, height work, confined spaces, mining, and machinery. Easiest to explain and to enforce consistently.
• A stated low threshold: used mainly in hospitality and office settings where the risk profile is different. Defensible only if the number and the reasoning are documented.
What is not defensible is a threshold that changes with how urgent the dispatch is.
The device has to be able to defend the number
If your policy turns on a reading, the instrument producing it needs to be worth arguing about. That means a fuel-cell sensor rather than a semiconductor one for anything disciplinary, a printer or data log for records, and a calibration schedule with dates that someone actually owns.
A semiconductor unit at a gate is fine for a first pass on a large gathering. Anything that can cost a person their shift or their job should be fuel-cell based, with the calibration certificate on file. For screening large numbers quickly, a passive unit plus a fuel-cell confirmatory device at the security cabin is the practical combination.
Before ordering, run through Buying an Alcohol Breath Analyser Online: A Purchase Manager's Verification Checklist, and if you are comparing local availability against specification, Alcohol Tester Near Me: How to Buy the Right One, Not the Nearest One covers that trade-off. Families wanting a unit for the car or for a teenager at home have a different set of requirements, covered in Home Breath Alcohol Analyzer: How It Works and How to Choose One.
Back to the slip on the desk
0.021 is below the Indian driving threshold. It is also not zero, which means the driver either consumed alcohol recently or has something in his mouth.
The correct action costs 15 minutes: water, wait, retest, record both. If the second reading is zero, log it and dispatch. If it holds, the vehicle stays, and the paperwork will show that the decision was made by a procedure rather than by a mood.
That is what a normal range actually means in practice. Not a number you can hide inside, but a baseline you can prove you were working from.