Bitumen Certificate of Analysis: How to Read, Verify and Use It
What a Certificate of Analysis actually is
A COA is a laboratory document reporting measured results obtained on a sample drawn from one identified quantity of bitumen.
A Certificate of Analysis reports measured values for a defined parcel — a production batch, a storage tank, or the quantity filled from either. It answers one narrow question: what did this material measure, on this date, by these test methods, on a sample drawn from this point. Everything that makes the document useful follows from how tightly it is tied to a physical quantity of bitumen sitting somewhere.
The COA against the Technical Data Sheet
These two documents are routinely treated as interchangeable, and they are not. A Technical Data Sheet describes the grade. It carries the specification band — penetration 60–70 dmm, softening point 49–56 °C, flash point minimum 250 °C — plus handling temperatures and a general product description. It is written once and reissued unchanged for years, and it is intended to be true of every batch the producer makes. It is a statement of intent.
A Certificate of Analysis describes one parcel. Penetration 64 dmm. Softening point 51.6 °C. Sampled from tank 7 on 14 June, tested on 15 June, released by a named chemist. It is a statement of fact, and it is the only one of the two documents that can support a quality claim.
The practical consequence is simple. A supplier who answers a request for a COA by sending a data sheet has not answered the request. That substitution happens often enough in the export trade that it is worth treating as information in itself: either the batch has not been tested yet, or the results are not ones the seller wants read line by line.
What a COA is not
- It is not a warranty. The warranty lives in the sale contract. The certificate is evidence that the warranty was, or was not, met. A COA with no contractual specification behind it commits nobody to anything.
- It is not proof of quantity. Weight and volume are established by the draft survey, the weighbridge tickets or the drum count, and by the inspection certificate — not by the laboratory report.
- It is not automatically independent. Most COAs are issued by the producer’s own laboratory. That is normal practice and usually reliable, but structurally it is the seller testing the seller’s goods. Independence has to be bought separately.
- It is not a substitute for your own specification. A certificate can be entirely accurate and still describe a binder that is wrong for your climate, your traffic loading or your national standard. Conformity is judged against your specification, not against the seller’s.
Who issues it, and how much weight each carries
Three sources appear in the trade, in ascending order of independence. The refinery laboratory, testing at the point of production, closest to the batch record. The terminal, blending plant or filling station laboratory, testing what is actually going into your drums or tank, which may be a different thing from what left the refinery. And an independent inspection company — SGS, Intertek, Bureau Veritas, Cotecna or an accredited national laboratory — sampling and testing on instruction from one or both parties.
All three are legitimate documents. They carry very different weight when a cargo is contested. Where buyer and seller are new to each other, or where the parcel value justifies the cost, specify the third one — and specify it in the contract, before the letter of credit is opened, because adding it afterwards means amending the credit.
COA, TDS, SDS, inspection report and origin certificate: which document does what
Five documents travel with most bitumen shipments and each proves something different. Confusing them is the most common reason a buyer discovers too late that nothing was actually verified.
| Document | What it describes | Batch-specific | Typically issued by | What it proves |
|---|---|---|---|---|
| Certificate of Analysis (COA) | Measured test results for one identified batch, tank or parcel | Yes | Refinery, terminal or independent laboratory | That this parcel was tested and what it measured |
| Technical Data Sheet (TDS) | The specification band, handling guidance and general description of the grade | No | The producer or supplier | What the grade is intended to be |
| Safety Data Sheet (SDS / MSDS) | Hazards, handling, storage, first aid and transport classification | No | Producer or supplier, in GHS format | How the material must be handled and declared |
| Third-party inspection report | Independent sampling and testing, plus quantity and packing condition at the load point | Yes | SGS, Intertek, Bureau Veritas or equivalent | That an independent party drew the sample and obtained these results |
| Certificate of Origin | Country in which the goods were produced | No | Chamber of commerce | Origin, for customs classification and duty treatment |
The sixteen fields a complete COA must carry
Read the header block before the results. Most defective certificates fail on identification, not on chemistry — and if the identification is missing, analysing the values is wasted effort.
| Certificate field | What a complete COA shows | What its absence means for you |
|---|---|---|
| Certificate number | A unique serial that can be quoted in the invoice, the letter of credit and any claim | There is no reference to cite; the document cannot be tied to a transaction |
| Issuing laboratory | Full name and address of the laboratory that ran the tests, with contact details | You cannot ask anyone to confirm the certificate exists |
| Product and grade claimed | Exact designation and the standard claimed against, for example Bitumen 60/70 to ASTM D946 | The certificate cannot be matched to the contract description of goods |
| Batch, lot or tank number | The production batch or storage tank the sample was drawn from | The results are attached to nothing physical — the single most common defect |
| Quantity covered | Tonnage and packing the batch represents, for example 300 MT in 2,000 new steel drums | You cannot tell whether the certificate covers your parcel or a fraction of it |
| Production or blending date | When the batch was produced or blended | You cannot judge how long the material sat in a hot tank before loading |
| Sampling date | The date the sample was drawn, which must precede the test date | The result may belong to different material entirely |
| Sampling point | Tank outlet, filling line, drum, or a composite across the parcel | A sample from one drum at the container door does not represent the load |
| Sampling method | The standard used to draw the sample, normally ASTM D140 | A non-representative sample makes every number below it meaningless |
| Test date | When the tests were actually performed | A long gap after sampling raises questions about sample storage and identity |
| Property list | Every property the contract specification requires, with none omitted | Silent omission is how weak certificates pass unchallenged |
| Test method per property | The standard designation on every line — ASTM D5, D36, D92, D2042 and so on | You cannot verify the correct test was run, or catch the wrong one |
| Unit per property | dmm, °C, wt %, vol %, poise, centistokes | A figure without a unit is not a result |
| Specification limit per property | The contract minimum and maximum printed alongside each measured value | Every line must be cross-referenced by hand, and errors go unnoticed |
| Measured value per property | The actual figure obtained, not the specification band repeated | Copied limits mean either nothing was measured or nothing is being disclosed |
| Signature, name, title and issue date | The signature and printed name of the chemist or QC manager releasing the result, with the date and page numbering | No accountable person stands behind the document, and pages can be dropped invisibly |
What a complete COA looks like: Bitumen 60/70
The header of the certificate below would carry: certificate number, product Bitumen 60/70 named against the exact specification the contract names, batch or tank reference, quantity covered, production date, sampling point (tank outlet, composite sample to ASTM D140), sampling date, test date, issuing laboratory with address, and the signature and printed name of the releasing chemist. The results table then reads as below. This is an illustrative layout for teaching purposes, not a certificate for any actual cargo, and no laboratory or batch identity is shown because inventing one would defeat the point of the page.
| Property | Test method | Unit | Contract limit | Measured value | Margin to limit |
|---|---|---|---|---|---|
| Penetration at 25 °C, 100 g, 5 s | ASTM D5 | dmm | 60–70 | 64 | 4 above the floor, 6 under the ceiling |
| Softening point, ring & ball | ASTM D36 | °C | 49–56 | 51.6 | 2.6 above the floor |
| Ductility at 25 °C, 5 cm/min | ASTM D113 | cm | min 100 | > 100, no break at full travel | Instrument travel reached |
| Flash point, Cleveland open cup | ASTM D92 | °C | min 250 | 306 | 56 above the floor |
| Solubility in trichloroethylene | ASTM D2042 | wt % | min 99.0 | 99.72 | 0.72 above the floor |
| Specific gravity at 25 °C | ASTM D70 | — | 1.01–1.06 | 1.032 | Mid-band |
| Loss on heating, 163 °C / 5 h | ASTM D1754 (TFOT) | wt % | max 0.2 | 0.08 | 0.12 under the ceiling |
| Penetration of TFOT residue at 25 °C | ASTM D5 on D1754 residue | dmm | Report | 57 | Feeds the line below |
| Drop in penetration after TFOT | Calculated from the two rows above | % of original | max 20 | 11 | 9 under the ceiling |
| Spot test | AASHTO T102 (withdrawn by AASHTO, still called up by some national and export specifications) | — | Negative | Negative | Conforms |
| Water content | ASTM D95 | vol % | max 0.2 | Nil | Below the method detection limit |
Internal consistency: eight cross-checks you can run yourself
Bitumen properties are not independent variables. They are different measurements of the same material, so they constrain one another. A certificate written at a desk rather than produced in a laboratory usually breaks at least one of these relationships, and none of the checks below requires equipment.
| Cross-check | What a coherent certificate shows | What an incoherent result suggests |
|---|---|---|
| Penetration against softening point | For straight-run paving bitumen the two move in opposite directions: a penetration near the soft end of 60/70 normally comes with a softening point near the low end of its band | A high penetration reported alongside a high softening point describes a blown or polymer-modified binder, not straight-run paving bitumen — or two numbers written independently of each other |
| Penetration index | PI = (1952 − 500 log P − 20 T) ÷ (50 log P − T + 120), with P the penetration in dmm and T the softening point in °C. Straight-run paving grades normally land between roughly −1 and +1 | A PI well above +2 points to an oxidized or blended product being sold as paving grade; a value far outside the normal range on both sides usually means the two inputs do not belong to the same material |
| Residue penetration against original | Ageing hardens bitumen, so the penetration of the TFOT or RTFOT residue is always lower than the original penetration | A residue penetration equal to or higher than the original is physically impossible and means the residue was never tested |
| Retained penetration arithmetic | The percentage figure reconciles with the two penetration values printed above it, to within rounding | A retention percentage that does not reconcile was not calculated from the results on the same page |
| Loss on heating against flash point | A paving grade loses only a fraction of a percent of mass at 163 °C and flashes well above 250 °C | High mass loss with a depressed flash point indicates volatile contamination — cutback, solvent or slop carried over in the tank |
| Solubility against specific gravity | Genuine paving bitumen is above 99 % soluble in trichloroethylene with a specific gravity of roughly 1.01 to 1.06 | Falling solubility with a rising specific gravity is the classic signature of extension with mineral filler |
| Reported precision against the method | Penetration to the nearest whole dmm, softening point to a tenth or two-tenths of a degree, solubility to two decimals | Softening point quoted to three decimal places, or penetration to 0.01 dmm, claims a precision the test method cannot deliver |
| Flash point method against product | Cleveland open cup (ASTM D92) for paving and oxidized grades; Tag open cup (ASTM D3143) for cutbacks, whose flash point is specified in tens of degrees rather than hundreds — MC grades at a minimum of 38 °C | ASTM D92 on a cutback certificate is the wrong method on the one line whose purpose is safety, and a cutback certificate quoting a flash point above 200 °C has almost certainly been copied from a paving grade template |
Nine signs of a weak or fabricated certificate
None of these is proof of bad faith on its own. Each is a question that deserves an answer before the cargo is filled, and two or three together are a reason to stop and appoint an inspector.
Values sitting on the limits
Penetration reported as exactly 60 or exactly 70, softening point exactly 49.0, loss on heating exactly 0.20. Real measurement scatters inside the band. A certificate that reproduces the specification is reporting the specification, not the batch.
Identical figures across batches
Two shipments three months apart with the same values to the same decimal place. Refinery feedstock and processing vary; consecutive batches never measure identically. Identical certificates mean one template used twice.
No batch or tank number
Without an identifier the certificate is attached to no physical quantity. It cannot be traced back to a production record, it cannot be matched to your drums, and it will not support a claim.
No test methods named
A column of numbers with no ASTM, EN or IS designation cannot be verified. It also conceals whether the wrong method was used — which matters most on flash point and on viscosity, where several different tests share one property name.
Solubility missing
Solubility in trichloroethylene is the anti-adulteration line. It is inexpensive to run and it is the line most often quietly dropped, because extension with mineral filler is the most common form of adulteration in the trade.
No ageing residue tests
Loss on heating and the drop in penetration afterwards predict how the binder survives the mixing plant. They are the best early warning of premature pavement cracking, and their absence removes it.
Sampling not described
No sampling date, no sampling point, no reference to ASTM D140. Every figure can be perfectly accurate and still belong to material that is not yours. Sampling is what connects the laboratory to the cargo.
Dates that do not sequence
A test date before the sampling date, a certificate issued before the batch was produced, or a sampling date after the bill of lading. These are the errors template reuse produces, and they are visible in seconds.
No signature or laboratory identity
An unsigned document on a letterhead nobody can call is a formatting exercise. Ask for the laboratory name, address and the printed name and title of the person releasing the result.
How to make the certificate actually protect you
Six steps, in this order. The first two decide whether the rest are worth doing, and both happen before any bitumen moves.
Write the certificate into the contract
Name the properties, the test methods, the limits, who issues the certificate, and what happens if a result falls outside. A contract saying only “quality as per seller’s COA” makes the seller’s own document the specification, which is the same as having no specification at all.
Ask for it against a nominated batch, before filling
Request the certificate for the specific tank or batch that will be drawn against your order, and read it before drums are filled or the vessel loads. After the cargo sails, your remedies narrow from rejection to a claim.
Check identification before values
Batch or tank number, quantity covered, sampling point and date, test date, issuing laboratory, signature. If any of these is missing, the numbers underneath cannot be tied to your cargo and analysing them is wasted effort.
Run the arithmetic and the cross-checks
Recalculate the retained penetration from the two penetration figures. Check the date sequence. Check the reported precision against what each method can deliver. Check penetration against softening point. Two minutes, no equipment.
Appoint an inspector at the load point
Independent sampling to ASTM D140, testing at an accredited laboratory, plus quantity and packing condition, with seal numbers recorded on the report. Agree the scope in writing before the inspector is nominated — which properties are tested, from how many sampling points, and whether the mandate covers quantity and packing as well as quality. An inspection certificate that only counts drums verifies nothing about the binder, and who pays the inspection fee is a contract term like any other.
Seal and hold retained samples
Have the inspector draw at least three sealed samples: one to the testing laboratory, one held by the seller, one held by the buyer or the inspector. Record the seal numbers on the inspection certificate. Without a sealed retained sample, a destination test result is one laboratory’s word against another’s.
The COA in the letter of credit, and in a claim
A certificate that is technically sound can still be commercially useless if the credit was drafted carelessly or the contract has no discrepancy mechanism.
What the bank actually checks
A documentary credit pays against documents, not against goods. Under UCP 600, banks examine a presentation on its face to decide whether the documents appear to constitute a complying presentation. They do not test bitumen, they do not compare a penetration value against your project specification, and they are not required to. Two consequences follow directly.
First, if the credit calls for a “Certificate of Analysis” without stipulating who issues it or what data it must contain, the bank will accept a document that appears on its face to be a Certificate of Analysis and is consistent with the other documents presented. A one-line sheet with the grade name and a signature can satisfy that requirement. Second, data in the documents must not conflict with data in the other documents or in the credit — so a certificate whose description of goods, batch reference or dates contradicts the invoice or the bill of lading is a genuine discrepancy the bank can act on.
Drafting the credit clause
Put the detail into the credit rather than trusting a generic document name. A workable clause names four things:
- Who issues it — the producer’s laboratory, or a named class of independent inspection company.
- What it must contain — the batch or tank number, the sampling date and point, the test date, and each specified property with its test method and measured result.
- What it must state — that the results conform to the specification named in the contract, with that specification reproduced or referenced unambiguously.
- When it is dated — issued on or before the date of the bill of lading, so the testing cannot post-date the loading.
Anything you leave vague, the bank will read in the seller’s favour, because the bank’s duty is to the documents in front of it and not to your pavement.
How the COA works in a quality claim
When a cargo underperforms at destination, the argument is almost never about whether bitumen is out of specification. It is about whose sample and whose laboratory. A claim that succeeds usually has four elements in place before the dispute begins:
- A sealed retained sample traceable by seal number to the parcel, drawn at the load point in the presence of both parties or an inspector, and held by both sides.
- A load-port result from a laboratory the seller cannot dismiss as the buyer’s own.
- A destination result from an accredited laboratory, obtained on a sample drawn under a defined procedure rather than from whichever drum was easiest to open.
- A contract clause that says what happens on a discrepancy — rejection, price allowance against a stated scale, or referral to an agreed referee laboratory whose result binds both parties.
The referee clause is the one most often left out and the one that most often decides the outcome. Without it, two conflicting certificates simply cancel each other and the argument becomes a negotiation about commercial relationship rather than about material. Agree the referee laboratory, the claim notice period and the sample retention period in the contract, and record the retention period on the inspection certificate so nobody can quietly let the samples expire while the correspondence continues.
What the certificate must show for grades other than penetration
The verification discipline is identical across the product range, but the property list a complete certificate carries changes with the grading system — and the performance grade certificate is where the widest gap sits between what is asserted and what was actually measured.
Check the certificate against the product you are buying, not against the last one you received. A template carried over from a paving grade is one of the easier defects to spot, because the wrong property names survive the copy.
- Viscosity grades. The certificate is built on absolute viscosity at 60 °C (ASTM D2171) and kinematic viscosity at 135 °C (ASTM D2170), with penetration and flash point alongside. Read the ageing line carefully: IS 73 reports the aged properties on RTFOT residue (ASTM D2872 / AASHTO T240), while ASTM D3381 reports them on TFOT residue (ASTM D1754). The two residues are not interchangeable, and a certificate that names neither has not told you which ageing test was run.
- Cutback grades. Distillation (ASTM D402) showing the fractions recovered to 190 °C, 225 °C, 260 °C and 316 °C and the residue at 360 °C; kinematic viscosity at 60 °C; Tag open cup flash point (ASTM D3143); water content; and the tests on the distillation residue — penetration, ductility and solubility. Without the residue tests you know how much solvent is in the drum but nothing about the binder left behind after it evaporates.
- Emulsions. Residue by distillation or evaporation, sieve test, particle charge, Saybolt Furol viscosity, settlement and storage stability, plus the tests on the recovered residue.
- Oxidized grades. Softening point (ASTM D36) and penetration (ASTM D5) as the paired defining properties, with loss on heating, solubility and flash point.
The performance grade certificate, and what cannot be inferred
A PG certificate is the one most often asserted and least often evidenced. The designation itself is a claim about measured rheology, so a certificate that prints “PG 64-22” and stops has reported nothing. A complete PG certificate under AASHTO M320 shows, at the stated temperatures:
- Rotational viscosity (AASHTO T316 / ASTM D4402), maximum 3 Pa·s at 135 °C — the pumping and mixing criterion.
- Flash point (ASTM D92), minimum 230 °C.
- DSR on original binder (AASHTO T315 / ASTM D7175), G*/sin δ minimum 1.00 kPa at the high grade temperature.
- RTFOT (AASHTO T240 / ASTM D2872): mass loss maximum 1.00 %, and DSR on the residue with G*/sin δ minimum 2.20 kPa at the high grade temperature.
- PAV (AASHTO R28 / ASTM D6521) followed by DSR on the aged residue, G*·sin δ maximum 5000 kPa at the intermediate temperature.
- BBR on the PAV residue (AASHTO T313 / ASTM D6648), creep stiffness S maximum 300 MPa and m-value minimum 0.300.
- Where the buyer’s specification is AASHTO M332, the MSCR result (AASHTO T350) with Jnr and percent recovery at the stated stress levels, which is what carries the S, H, V or E traffic designation.
The test temperatures on a PG certificate are not a free choice, which gives you a further arithmetic check that takes seconds. Under M320 the intermediate DSR temperature is (H + L) ÷ 2 + 4 °C and the BBR is run at L + 10 °C, where H and L are the two numbers in the grade designation. For PG 64-22 that is an intermediate temperature of (64 + (−22)) ÷ 2 + 4 = 25 °C and a BBR temperature of −22 + 10 = −12 °C. A certificate quoting different temperatures for the grade it claims has either tested a different grade or invented the header.
One point deserves stating plainly, because it is the source of a great deal of paper that looks like evidence and is not: a penetration grade cannot be converted to a PG grade on paper. There is no formula that turns penetration and softening point into a PG designation. The two systems measure different things — one an empirical consistency at a single temperature, the other rheological behaviour across a temperature range on original, RTFOT and PAV aged material. A PG grade exists for a binder only where the DSR, BBR and ageing tests were actually run on that binder and the results are on the certificate. If a supplier offers a 60/70 certificate with a PG designation added and no DSR or BBR data behind it, the designation is a marketing line, not a test result, and it will not survive a specification audit at destination.
Frequently asked questions about the bitumen COA
What is a bitumen Certificate of Analysis?
It is a laboratory document reporting the measured test results for one identified quantity of bitumen — a batch, a tank or a defined parcel. A complete certificate identifies the batch, the sampling point and date, the test date and the issuing laboratory, and for every property it shows the test method, the measured value and the specification limit, over a signature.
What is the difference between a Certificate of Analysis and a Technical Data Sheet?
A Technical Data Sheet describes the grade in general: the specification band, handling temperatures and product description. It is reissued unchanged for years. A Certificate of Analysis describes one parcel and reports what that parcel actually measured on a stated date. The data sheet is a statement of intent; the certificate is a statement of fact and is the only one of the two that can support a claim.
Who should issue the Certificate of Analysis?
For established supply relationships, the producer’s own laboratory is normal and generally reliable. For a first order, an unfamiliar counterparty or a high-value parcel, specify an independent inspection company sampling and testing at the load point. Whichever you choose, name it in the contract before the letter of credit is opened, because adding it later requires an amendment.
What should I do if the COA values sit exactly on the specification limits?
Ask for the raw laboratory worksheet and the batch record, and ask for certificates from two other recent batches of the same grade. Genuine production data scatters inside the band and no two batches measure identically. If the numbers on all three certificates are the same, or all sit on the limits, treat the documents as unverified and appoint an independent inspector before the cargo is filled.
Does one Certificate of Analysis cover a whole shipment?
Only if the certificate says so. A COA covers the batch or tank it names, and the quantity it states. A 500 MT order drawn from three tanks needs certificates covering all three, or a composite certificate that identifies each tank contributing to the parcel. Check that the quantity on the certificate is at least the quantity on your invoice.
Is a Certificate of Analysis the same as a Certificate of Quality or a Certificate of Conformity?
Not necessarily. Certificate of Quality is often used as a synonym for a COA, but it is sometimes issued as a short statement without any test data. A Certificate of Conformity typically states only that the goods conform to a named standard, again without figures. Neither substitutes for a certificate carrying measured values, test methods and specification limits. If the document has no numbers on it, ask for one that has.
What should my letter of credit say about the COA?
Name who issues it, what it must contain — batch or tank number, sampling date and point, test date, and each property with its test method and measured result — what it must state about conformity to the contract specification, and that it must be dated on or before the bill of lading date. Banks examine documents on their face under UCP 600 and will not compare your values against your project specification, so whatever the credit leaves unstated is not being checked by anyone.
My destination laboratory result differs from the COA. What now?
Retrieve the sealed retained sample drawn at the load point and have it tested by the referee laboratory named in the contract. Sampling, storage and handling explain many discrepancies, and a result from a sample of unknown history will not settle the argument. Give notice of the claim inside the contractual period, keep the seals and the chain of custody documented, and do not consume or blend the remaining cargo until the position is resolved.
Have a Certificate of Analysis checked before you pay
Send the certificate together with your project specification and it will be read line by line — identification, test methods, measured values against limits, and the internal cross-checks — before any offer is priced.