One number defines VG-20 — its absolute viscosity at 60 °C — and IS 73:2013 attaches that number to a single job: paving in cold climate regions.
The designation is an instruction to a laboratory rather than a brand. The letters mark the grading system, viscosity rather than penetration, and the figure that follows is the nominal viscosity at 60 °C counted in hundreds of poise. VG-20 is therefore built around 2000 poise, and IS 73:2013 will accept any batch that lands between 1600 and 2400 poise when run in a vacuum capillary viscometer to IS 1206 (Part 2) — the Indian method matching ASTM D2171. In SI units the band is 160 to 240 Pa·s, because one poise equals 0.1 Pa·s. The same nominal-2000-poise-plus-or-minus-400 window is used by grade AC-20 in the older ASTM D3381 viscosity-graded system, which is the closest genuine counterpart VG-20 has in any other standard — closer than any penetration grade, because it is built on the same measurement at the same temperature.
Grading at 60 °C is deliberate: that is approximately the hottest condition the binder meets inside a pavement, and it is where permanent deformation is decided. The second viscosity control, a minimum of 300 cSt at 135 °C to IS 1206 (Part 3) / ASTM D2170, sits inside the range where the binder is handled at the plant. Between them the standard pins the material at the two temperatures that determine whether a plant can build the road and whether the road survives the summer. What IS 73:2013 does not do — and this matters more for VG-20 than for any other grade in the standard — is measure anything at low temperature.
The four viscosity bands in IS 73:2013 are not laid end to end. Read them as a single number line and the structure of the standard becomes clear:
Two consequences follow, and both are specific to buying VG-20. At the soft end, a parcel offered as VG-20 that actually measures 1350 or 1500 poise is not a marginal VG-20 — it is not VG-10 either, and it belongs to no grade in the standard. At the stiff end, a batch measuring exactly 2400 poise satisfies the VG-20 ceiling and the VG-30 floor at the same time on that one line, so the viscosity figure alone does not always identify which grade a certificate is claiming. Penetration and softening point are what separate the two at that boundary.
Because the grade number tracks viscosity directly, stiffness rises with the number — the opposite of penetration grading, where the number falls as the binder hardens:
IS 73:2013 assigns each grade a normal field of use, and VG-20's is paving in cold climate regions. In Indian practice that maps to the Himalayan belt and the high-altitude districts — the states and territories where winter pavement temperatures fall far below anything the plains experience — together with the higher elevations of the north-east. It is a small share of the national road network and a very small share of national binder demand, which is the root of almost everything commercial on this page. VG-20 is also not the standard's only answer to cold: grade selection under Indian practice is keyed to site air temperature together with commercial traffic volume, and where winters are severe but traffic is light the answer steps down to VG-10. That narrows VG-20's territory again, to cold sites that nonetheless need a structural layer.
It is worth being precise about the basis of that assignment. VG-20 is the cold-climate grade because it is softer, less temperature susceptible at the cold end by inference, and therefore less likely to be brittle in winter than VG-30. It is not the cold-climate grade because the standard measured its low-temperature behaviour, because IS 73:2013 contains no bending beam rheometer test, no fracture or critical cracking temperature, and no low-temperature limit of any kind. The assignment is a relative statement about hardness at 25 °C and 60 °C, projected downwards. Where a project's winter design temperature is genuinely severe, that distinction stops being academic — see the note at the end of the next section.
Eight lines, and that is the whole of the VG-20 requirement. Each is shown with the Indian test method that produces it and the international method an export certificate may substitute for it.
| Property | Test method | Unit | Min | Max |
|---|---|---|---|---|
| Absolute viscosity at 60 °C | IS 1206 Part 2 / ASTM D2171 | poise | 1600 | 2400 |
| Kinematic viscosity at 135 °C | IS 1206 Part 3 / ASTM D2170 | cSt | 300 | — |
| Penetration at 25 °C, 100 g, 5 s | IS 1203 / ASTM D5 | dmm (0.1 mm) | 60 | — |
| Softening point, ring & ball | IS 1205 / ASTM D36 | °C | 45 | — |
| Flash point, Cleveland open cup | IS 1448 (P:69) / ASTM D92 | °C | 220 | — |
| Solubility in trichloroethylene | IS 1216 / ASTM D2042 | wt % | 99.0 | — |
| Viscosity ratio at 60 °C, on RTFOT residue | IS 9382 / ASTM D2872, then IS 1206 Part 2 | ratio | — | 4.0 |
| Ductility at 25 °C, 5 cm/min, on RTFOT residue | IS 1208 / ASTM D113 | cm | 50 | — |
Eight lines, each closing off a specific failure mode. On a cold-climate binder two of them carry more weight than the rest, and one important risk is not covered at all.
This is the line the grade is named for and the line a marginal batch fails first. Below 1600 poise the binder is softer than VG-20 at pavement service temperature and will deform more readily under load in warm weather; above 2400 poise it is no longer VG-20 at all. For a cold-climate project, where the batch sits inside the band is a genuine engineering question rather than a formality. A parcel measuring 2350 poise is compliant VG-20 and is also, within measurement uncertainty, the stiffest material the grade permits — effectively borderline VG-30. If the site is severely cold, ask for material in the lower half of the band and write that narrower range into the contract, because IS 73:2013 will accept 2400 poise as VG-20 and that is the least suitable VG-20 available.
Measured by gravity flow through a capillary viscometer to IS 1206 Part 3 / ASTM D2170, with a floor of 300 cSt — 50 cSt below the VG-30 requirement and 50 above VG-10. The plant-floor question it settles is whether the binder will move through the lines and wrap the stone at mixing temperature. Read against the 60 °C figure it answers a second, less obvious one. Take two certificates that both report 2000 poise at 60 °C, one showing 310 cSt at 135 °C and the other 430. The 310 cSt binder has lost more stiffness over the same 75 °C rise, and a line that steep going up is equally steep coming down — which is the direction that matters, because a cold-region pavement spends its winter at the bottom of it. So on VG-20 the 300 cSt floor is doing more than the plant-workability job it does on VG-30 and VG-40. It is the only lever IS 73:2013 has on the slope of the viscosity–temperature curve, and the slope is the whole reason a softer grade was specified.
IS 73:2013 sets a minimum of 60 dmm for VG-20 and no upper limit. Across the four grades the penetration minima descend as stiffness rises — 80, 60, 45 and 35 dmm for VG-10, VG-20, VG-30 and VG-40 — which tells you what the line is for. It is not a hardness classification, since viscosity already performs that job. It is a temperature-susceptibility guard: it prevents a refiner from meeting the 1600–2400 poise band with an over-blown, highly temperature-susceptible residue that would be hard and brittle at ambient temperature. Because VG-20 exists to serve cold regions, this guard is the second most important line in its table. A certificate showing 1900 poise with a penetration of 61 dmm describes a very different binder from one showing 1900 poise at 78 dmm, and in a cold climate the second is the safer material.
Ring and ball to IS 1205 / ASTM D36, minimum 45 °C, with no ceiling. A batch sitting properly inside the viscosity band will normally clear it. Where a certificate shows a softening point at the floor together with a viscosity near 1600 poise, read the pair as a single finding: it indicates a soft parcel that will be marginal if the same material is diverted to a warmer site.
The rolling thin film oven test (IS 9382, equivalent to ASTM D2872) simulates the hardening the binder undergoes in the drier, the mixer and short-term storage. The laboratory measures the viscosity of the residue at 60 °C and divides it by the viscosity of the original binder. IS 73:2013 allows a maximum ratio of 4.0, the same ceiling it applies to all four grades — but the consequence is not the same for all four. The arithmetic is worth doing once. A VG-20 at the top of its band that ages by the full permitted factor leaves the plant near 9600 poise at 60 °C. A mid-band VG-30 at 3000 poise reaches that same 9600 at a ratio of 3.2 — comfortably inside the identical 4.0 ceiling. A fully compliant VG-20 can therefore arrive at the paver stiffer than a fully compliant VG-30, and nothing on the face of either certificate says so. Put plainly, a cold-climate binder that spends its whole ageing allowance has surrendered most of the softness it was specified for. On VG-20 this is the line to read first after the grade viscosity itself, and it is the line that weak certificates leave out.
IS 1208 / ASTM D113 pulls a briquette of the aged residue apart at 25 °C, 5 cm/min, and VG-20 must hold the thread for at least 50 cm. That floor sits above VG-30's 40 cm and VG-40's 25 cm, and below VG-10's 75 cm — the standard demands more retained stretch from the softer grades. Because it is run on RTFOT residue rather than on original binder, it is not comparable with the 100 cm minimum quoted for unaged material on penetration-grade export sheets, and setting the two figures side by side in a tender evaluation is a common and avoidable error. What the line tests is whether the binder still has cohesion and extensibility after the plant has aged it, which for a pavement that will be pulled about by thermal movement all winter is the most relevant thing IS 73:2013 measures.
The Cleveland open cup flash point floor is 220 °C to IS 1448 (P:69) / ASTM D92, and IS 73:2013 applies it unchanged across all four grades — it is the one requirement where the softest and the stiffest grade in the standard are held to exactly the same number. It is the figure a tank farm sets its heating limits from and the figure an insurer will ask for. Watch for a clash where a VG-20 requirement has been dropped into a contract template originally drafted for penetration grades, which routinely specifies 250 °C: the cargo can be fully compliant with IS 73:2013 and still be off-contract. Decide which figure governs while the contract is being drafted rather than when the cargo is alongside.
Solubility in trichloroethylene, minimum 99.0 % to IS 1216 / ASTM D2042, answers a blunter question: is the drum full of bitumen, or bitumen plus something insoluble. The line carries more weight on a soft grade than on a hard one, because the cheapest route into a low viscosity band is to extend a heavier stock, and the penetration floor alone will not always catch that. On VG-20 the solubility result and the 60 dmm penetration floor are doing complementary authenticity work rather than repeating each other.
IS 73:2013 controls VG-20 at 25 °C, 60 °C and 135 °C. It never tests the binder at a temperature a cold-region pavement will actually reach in January. There is no bending beam rheometer stiffness or m-value, no direct tension test and no critical cracking temperature anywhere in the standard. Specifying VG-20 is therefore a sensible relative decision — it is the softest grade in the standard that can still carry traffic in a structural layer — but it is not a measured guarantee of low-temperature performance. Where winter design temperatures are severe, the technically correct control is a performance-graded binder with a stated low-temperature grade, determined by bending beam rheometer testing, or a polymer-modified binder. If the project specification names VG-20, supply VG-20; but if you are the one choosing the binder for a genuinely cold site, know what the certificate does and does not prove.
VG-20 is best understood by reading what sits either side of it, because the commercial pressure on this grade comes from both directions at once. Below is the whole of IS 73:2013 in one table, with the VG-20 column bracketed by the two grades most often supplied in its place.
| Property | VG-10 | VG-20 | VG-30 | VG-40 |
|---|---|---|---|---|
| Absolute viscosity at 60 °C, poise | 800–1200 | 1600–2400 | 2400–3600 | 3200–4800 |
| Kinematic viscosity at 135 °C, cSt, min | 250 | 300 | 350 | 400 |
| Penetration at 25 °C, dmm, min | 80 | 60 | 45 | 35 |
| Softening point, ring & ball, °C, min | 40 | 45 | 47 | 50 |
| Flash point, Cleveland open cup, °C, min | 220 | 220 | 220 | 220 |
| Solubility in trichloroethylene, %, min | 99.0 | 99.0 | 99.0 | 99.0 |
| Viscosity ratio at 60 °C after RTFOT, max | 4.0 | 4.0 | 4.0 | 4.0 |
| Ductility at 25 °C after RTFOT, cm, min | 75 | 50 | 40 | 25 |
| Normal field of use | Spray work, surface dressing, emulsion and cutback feedstock; also light paving where winters are too severe for VG-20 | Paving in cold climate regions | Paving in hot climates and under heavy traffic | Very heavy, slow-moving and channelised traffic |
VG-20 is a real, standardised, fully specified grade that is nonetheless bought far less often than VG-10, VG-30 or VG-40. It is worth being straightforward about why, because the reasons change how a VG-20 order has to be placed.
VG-20's field of use is cold-climate paving, and cold-climate zones are a minority of the road network in the countries that use IS 73. They are also the zones with the shortest construction season: high-altitude and snow-affected districts compress a year's paving into a handful of months, and access roads to those sites are themselves seasonal. Demand for VG-20 therefore arrives in bursts against a short window rather than as the steady baseload that keeps a grade continuously available. VG-30, by contrast, is consumed everywhere, all year.
Where a project needs a soft, sprayable binder — surface dressing, prime and tack work, or feedstock for emulsion and cutback manufacture — the answer is VG-10. Where a project needs a general-purpose paving binder, the answer is VG-30. VG-20's territory is the specific intersection of the two: conventional structural hot-mix paving, in a cold place. That intersection is real and the grade exists for good engineering reasons, but it is narrow, and specification writers working from habit — or from what the nearest asphalt plant already has in its binder tank — frequently write VG-30 across the whole project anyway.
Most of the export market still thinks, quotes and holds inventory in penetration grades, and VG-20 does not land cleanly on any of them. Published cross-references place it anywhere between 60/70 and 80/100 depending on crude source and on who compiled the table, and both mappings are arguable from opposite ends of the specification: the 1600–2400 poise band leans towards 60/70, while the 60 dmm penetration floor and the 45 °C softening point floor lean towards 80/100. VG-10 and VG-40 do not have this problem — each sits recognisably beside a grade a trader already holds — and VG-30 does not have it either, because it is stocked in its own right. VG-20 alone straddles a gap. A buyer working from penetration habits therefore has no familiar grade to reach for when a specification says VG-20, and the path of least resistance is to take whichever neighbouring grade is already in the supplier's tank.
Treat every one of those mappings as orientation and nothing more. A penetration figure cannot evidence IS 73:2013 compliance in either direction, because the standard defines the grade by absolute viscosity at 60 °C and puts only a floor under penetration — a batch reading 65 dmm may be VG-20, may be VG-30, and may be neither. The grade equivalence reference sets the systems out side by side with the same caveat attached.
A grade with thin, seasonal demand is not run continuously. VG-20 is generally produced or blended against confirmed orders, which means dedicating tankage, turning it over, and certifying a relatively small lot. None of that is difficult, but all of it takes planning, and it is the reason VG-20 rarely sits in ready stock at a loading terminal in the way VG-30 does. The practical effects on a buyer are consistent: more notice is needed than for VG-30, a minimum lot size usually applies, and the offer price reflects the cost of segregating and certifying a small parcel rather than tracking the mainstream grade.
It is the right call when the project specification names it; when the works are conventional hot-mix paving in a genuinely cold zone; and when the realistic alternative is a stiffer binder being laid into a cold base and asked to survive a hard winter. It is the wrong call when the site is hot or the traffic is heavy and channelised, where VG-30 or VG-40 belong; when the requirement is spray work or emulsion and cutback feedstock, where VG-10 belongs; and when winter design temperatures are severe enough that a measured low-temperature property is needed, where a performance-graded or polymer-modified binder is the honest answer. Choosing VG-20 because it is a middle number is not a reason. Choosing it because the climate is cold and the layer is structural is.
The grade covers conventional hot-mix paving in cold regions — the same work VG-30 does elsewhere, with a binder chosen to stay flexible through a hard winter.
The dense-graded surfacing layer on hill and high-altitude highways where the specification assigns the cold-climate grade. Thin surfacing sections cool quickly, and a softer binder holds workability further into the roller window.
The structural binder course beneath the surfacing, and usually the layer that decides the order quantity. A remote cold-region site that has gone to the trouble of securing a made-to-order grade will normally run it through the whole build-up rather than manage two binders and two heated tanks at the end of a seasonal supply road.
Lower-volume mountain and rural roads where a full dense-graded specification is not justified but the binder still has to survive freeze–thaw cycling.
Renewal and strengthening coats over pavements that have already been through one or more hard winters. Those cracks keep moving seasonally under whatever is laid on top of them, and a binder chosen for softness at least buys some tolerance of that movement before the pattern reappears through the new surface.
Work carried out at the ends of a short construction season, when ambient and base temperatures are low and the mix loses heat faster than the nominal laying temperature suggests.
Tenders in markets that draft their road specifications on IS 73 and MoRTH practice, and that contain genuinely cold high-altitude zones. The grade name travels with the specification even where the local supply chain quotes penetration grades.
Because VG-20 is graded by viscosity, its handling windows can be derived from the batch's own measured data rather than taken on trust from a table. The figures below are typical operating values; the method beneath them is the more useful part.
| Operation | Typical VG-20 value | Why it matters |
|---|---|---|
| Storage, short term | 145–160 °C | Enough to stay pumpable and no more; the window sits below the VG-30 equivalent because a softer binder does not need the extra heat to move |
| Storage, long term | below 145 °C | Prolonged hot storage raises the viscosity at 60 °C, and a batch already in the upper half of the band can cross the 2400 poise ceiling in the tank before it is ever used |
| Pumping and circulation | 130–160 °C | The lower end is workable on VG-20 where a harder grade would still be dragging; below it, line resistance climbs and pumps start to cavitate |
| Aggregate at the mixer | 150–170 °C | The aggregate, not the binder, carries most of the heat into the mix — so this is the number that actually ages the binder film, on contact and irreversibly |
| Mixing with aggregate | 145–160 °C | VG-20 reaches mixing viscosity below the temperature VG-30 needs, but how far below depends on the batch; a plant changing grade must re-derive the target from the new certificate rather than carry the old setting across |
| Laying at the paver | not below 130 °C | In cold-weather work the mix loses heat far faster than the nominal delivery temperature suggests |
| Compaction, cut-off | above 85–90 °C | The softer binder buys slightly more roller window than VG-30 at the same lift thickness — on a cold site that margin is spent on cooling rate, not banked |
| Target binder viscosity for mixing | 170 ± 20 cSt | The rule the temperature column is derived from; the batch's own two viscosity results define the line it is read off |
| Target binder viscosity for compaction | 280 ± 30 cSt | The roller window, set the same way. On a cold site this is the limit that arrives first, and usually earlier than expected |
| Absolute maximum bulk temperature | do not exceed 175–180 °C | Above this, oxidation runs away and fuming turns heavy; a batch near the 2400 poise ceiling has almost no room to harden further before it leaves the grade entirely |
A VG-20 cargo is queried for different reasons than a VG-30 cargo. These four checks close off the problems that actually occur on this grade.
Confirm the measured absolute viscosity at 60 °C to IS 1206 Part 2 falls inside 1600–2400 poise, and note where in the band it sits. A certificate reporting 2450 poise is VG-30 material whatever the heading says, and a certificate reporting 1400 poise is not a grade at all. On a cold site, ask for the lower half of the band and put the narrower range in the contract.
Two numbers, both taken on rolling thin film oven residue to IS 9382 / ASTM D2872: viscosity ratio at 60 °C, maximum 4.0, and ductility at 25 °C, minimum 50 cm. On this grade the ductility floor is the one to weigh. At 50 cm it is the second-strictest in the standard, and it is the only line in IS 73:2013 that says anything at all about whether the aged binder can still stretch — which is the single property a cold-region pavement lives on. A loss-on-heating or retained-penetration figure evidences neither limit. Because VG-20 lots are small and made to order, ask at enquiry stage whether the RTFOT pair will actually be run on your lot rather than carried across from an earlier campaign.
VG-20 is rarely a stock item. Agree the lot size, the production and certification window, and whether partial shipment is acceptable, before you ask for a price rather than after. If the schedule cannot absorb the lead time, that is a conversation to have at enquiry stage — not a reason to accept a silent substitution.
VG-20 destinations are disproportionately remote and seasonal. New steel drums of 150 kg or 180 kg suit sites without heated storage; 1 MT jumbo or meltable bags suit a site with a melting unit and cut the steel waste that has to be carried back down; a bitutainer or bulk parcel suits a buyer with discharge and heating capability at the far end. Specify new drums explicitly. On a small campaign lot there is no second parcel to fall back on if a reconditioned drum contaminates part of the shipment, and no realistic prospect of a fast replacement.
It is the 1600 to 2400 poise grade of IS 73:2013. The number is the nominal absolute viscosity at 60 °C in hundreds of poise, so VG-20 sits around 2000 poise — 160 to 240 Pa·s in SI units — measured in a vacuum capillary viscometer to IS 1206 Part 2, which corresponds to ASTM D2171. Two things set VG-20 apart from the other three grades rather than the definition itself. The standard assigns it to cold-climate paving, and it is the softest grade IS 73:2013 puts into a structural layer. And the band immediately beneath it is empty: nothing between 1200 and 1600 poise is graded at all, so a VG-20 parcel that comes in soft has no lower grade to fall into. The remaining limits — 300 cSt at 135 °C, 60 dmm penetration, 45 °C softening point, 220 °C flash point, 99.0 % solubility and the two RTFOT results — are guards around that band rather than the grade itself.
Because it is the softest grade in the standard that is still intended for structural paving layers. A softer binder is less likely to be brittle when pavement temperatures fall and is better able to tolerate the thermal movement that causes low-temperature cracking. It is important to understand what that assignment rests on: IS 73:2013 tests the binder at 25 °C, 60 °C and 135 °C and contains no low-temperature test at all — no bending beam rheometer stiffness, no m-value and no critical cracking temperature. VG-20 is the cold-climate grade by inference from its hardness, not by direct measurement of low-temperature behaviour.
Three reasons compound. Its field of use is cold-climate paving, which is a small share of the road network and has a short construction season, so demand is both limited and seasonal. It is squeezed from both sides, because spray work and emulsion feedstock go to VG-10 while general paving goes to VG-30, leaving VG-20 only the narrow intersection of structural paving in a cold place. And most of the export market still stocks in penetration grades, where VG-20 falls between 60/70 and 80/100 rather than onto either, so a buyer has no familiar grade to reach for and tends to take whatever the supplier already holds. The practical result is that VG-20 is usually produced against orders rather than held in stock, so it needs more notice and generally carries a minimum lot size.
Not as a matter of course. VG-30 is a stiffer binder — 2400 to 3600 poise at 60 °C against 1600 to 2400 — and in a cold region that substitution moves risk toward low-temperature and reflective cracking, which is exactly what the cold-climate grade was chosen to avoid. The two grades also touch at 2400 poise without overlapping, so no single batch is genuinely both. If VG-30 is being offered because VG-20 is not available, treat it as a proposed specification change and obtain the engineer's written approval before accepting it. A substitution accepted verbally at the loading stage becomes the buyer's problem at the discharge stage.
VG-10 measures 800 to 1200 poise at 60 °C and VG-20 measures 1600 to 2400, so VG-20 is roughly twice as viscous at service temperature. VG-10 carries a higher penetration floor of 80 dmm against 60, a lower kinematic viscosity floor of 250 cSt against 300, a lower softening point floor of 40 °C against 45, and a higher post-RTFOT ductility floor of 75 cm against 50. In use, VG-10 goes to spray applications, surface dressing and emulsion or cutback manufacture, while VG-20 goes into structural hot-mix layers in cold regions. Note also that nothing between 1200 and 1600 poise is graded at all, so the two are not adjacent bands.
There is no single answer, and that is itself part of why the grade trades thinly. Published cross-references put VG-20 against 60/70 or against 80/100 depending on crude source and on who compiled the table, because VG-20 falls between the two rather than onto either. Treat any such mapping as approximate commercial orientation and never as interchangeability. No penetration grade can demonstrate IS 73:2013 compliance in any case: the standard defines the grade by absolute viscosity at 60 °C and sets only a floor under penetration, so a batch reading 65 dmm might be VG-20, VG-30 or neither. The one genuine like-for-like counterpart is AC-20 in the older ASTM D3381 viscosity-graded system, which uses the same nominal 2000 poise with the same plus-or-minus-400 window. Where a specification names VG-20, the Certificate of Analysis has to carry the IS 1206 Part 2 and Part 3 viscosity results together with the RTFOT pair.
No. The standard controls VG-20 at 25 °C, 60 °C and 135 °C only. There is no bending beam rheometer test, no direct tension test and no fracture or critical cracking temperature anywhere in it. The closest proxies it offers are the penetration floor of 60 dmm, which guards against a stiff and temperature-susceptible binder entering the grade, and the post-RTFOT ductility floor of 50 cm, which shows the aged binder still has cohesion and stretch. If a project's winter design temperature is severe, the technically correct control is a performance-graded binder with a stated low-temperature grade determined by bending beam rheometer testing, or a polymer-modified binder.
Every line in the specification table above, measured on your material, each with its method named — six on the binder as supplied and two on the rolling thin film oven residue. Beyond that, three checks matter more on VG-20 than on a stock grade. Read where inside 1600 to 2400 poise the batch actually sits, because on a cold site that position is a real engineering variable and a single small lot gives you no averaging across shipments to smooth it out. Confirm the RTFOT pair is physically present rather than assumed; it is the pair most often skipped when a small lot is certified under time pressure. And confirm the document is tied to your lot by batch or tank number, because a made-to-order grade invites a certificate copied over from an earlier campaign that described different material. The supporting file should also carry the Technical Data Sheet and Safety Data Sheet, the Certificate of Origin, and — on a grade this thinly traded, where you cannot benchmark the supplier against a stream of comparable shipments — an independent inspection at load port covering quality, quantity and packing condition is worth paying for rather than waiving.
Send quantity, packing, destination port and Incoterm. VG-20 is generally produced against orders rather than drawn from stock, so state your required shipment window in the first message and attach the project specification if one names IS 73:2013 or sets certificate content.