Every figure on DrillingFluidAdditives.com, from an API Spec 13A requirement to a discharge limit in 40 CFR 435, comes from a named primary source, is cited with its edition or date, and is checked again when that source changes.
Mud engineers, drillers and buyers rely on these numbers. A wrong edition, or a supplier value written as a requirement, misleads anyone who sets a mud weight or orders material for a drilling fluid, so every figure answers one question: which source, which edition, checked when?
The sections below cover eight source types, the rule for conflicting sources, edition labels, requirement values versus data-sheet values, hazard and discharge statements, units, dating and exclusions.
Which Sources Do the Figures Come From?#
Figures come from eight types of sources, led by standards bodies such as API and ISO and regulators such as the US EPA, OSPAR, Cefas and Miljodirektoratet, with supplier data sheets used only as labeled examples.
The table below lists the eight source types, examples of each and what each is used for.
| Source type | Examples | Used for | Outbound link |
|---|---|---|---|
| Standards bodies | API, ISO | requirement values, test procedures, editions | followed |
| Regulators and intergovernmental bodies | US EPA (eCFR, Federal Register), BOEM, BSEE, OSPAR, Cefas, OPRED, Miljodirektoratet, Havtil, EUR-Lex | discharge limits, notification and permit rules | followed |
| Chemical registers | ECHA (C&L Inventory, Candidate List), PubChem | hazard classification, EC and CAS numbers | followed |
| Public statistics and metrology | USGS Mineral Commodity Summaries, NIST | supply data, dated unit values, unit definitions | followed |
| Industry standards publisher | IADC | field formulas and conversion shortcuts | followed |
| Peer-reviewed and conference papers | SPE (OnePetro), AADE, Elsevier, ACS | test conditions, field data, mechanisms | followed |
| Trade journals, named in the sentence | Trenchless Technology, The Driller, Water Well Journal, JPT | field practice | nofollow |
| Supplier data sheets | one product per value | labeled product examples | nofollow |
Standards bodies, regulators, chemical registers, public statistics, the IADC and peer-reviewed publishers are linked as followed sources. Trade journals and supplier data sheets are named in the sentence and linked nofollow.
How conflicting sources are settled#
A newer official source wins over an older or secondary one, and a standard always wins over a supplier data sheet. For substance identity, ECHA wins for EC numbers and CLP classification, and PubChem wins for CAS numbers and structure.
Dates follow the same rule. When a reseller listing and the API Standards Plan give different publication dates for one document, the API date is the one written, for example API RP 13D, 8th edition, published 2026-04-30.
How Standards Editions Are Checked and Labeled#
Every standard is cited with its edition and date as checked on the publisher's own listing, such as API Spec 13A, 19th edition (2019) with Addendum 1 (2020), Addendum 2 (2022) and Errata 1 (2024). That is the current edition (API Standards Plan, checked 2026-10-27), and a 20th edition is in development.
API Spec 13A is a Specification, while API RP 13B-1, 13B-2, 13D and 13I are Recommended Practices. Every page that cites drilling fluid standards and rules gives the edition and date, and API RP 13B-1 is cited as the 6th edition, published 2026-01-15.
Three edition labels carry the remaining cases. "18th edition (2010) text" marks a value taken from the older API Spec 13A text, "ISO counterpart" names ISO 13500 without claiming it is identical to API Spec 13A, and "per the ballot draft, confirm against the published edition" marks a value read only in a public API ballot draft.
Requirement Values and Supplier Data-Sheet Values#
A requirement value is what a standard demands of every compliant material, a data-sheet value is what one supplier reports for one product, and the site never writes one as the other.
A product value carries the label "typical value of {product} ({company}) data sheet" on material, fluid-system, application and problem pages. A dose range becomes a "typical field range" only when two independent sources give it, and one product's temperature limit is never extended to its class.
The grade name "API 13A grade" applies only to the 13 materials the specification covers, such as barite, bentonite, polyanionic cellulose and xanthan gum. Scope, edition and the materials' API Spec 13A requirement values are tied to that one specification.
The table below lists the eight labels used on pages and what each means.
| Label | Meaning | Where it appears |
|---|---|---|
| "18th edition (2010) text" | value taken from the 2010 API Spec 13A text, not restated in the 19th edition text read | API 13A values for bentonite, attapulgite, sepiolite, CMC, starch, polyanionic cellulose, xanthan gum |
| "ISO counterpart" | ISO 13500 is the corresponding ISO document; equivalence is not claimed | standards and material pages |
| "per the ballot draft, confirm against the published edition" | only the public API ballot draft could be read | test pages citing API RP 13B-1 or 13B-2 values |
| "typical value of {product} ({company}) data sheet" | one supplier's figure for one product, not a requirement | material, fluid-system, application, problem pages |
| "typical field range" | range given by at least two independent sources | dose tables |
| "calculated" | computed by the site from stated inputs and fixed factors | dose and conversion tables |
| "e" after a year | USGS estimate | supply and unit-value statements |
| "checked {date}" | date the source was last read | edition and status statements |
How Hazard Classifications and Discharge Rules Are Stated#
Hazard classifications follow one order: the harmonized CLP classification where one exists, otherwise the majority ECHA C&L notified classification marked "no harmonized entry", otherwise "see supplier SDS".
Hazard lines appear only on material pages. A class hazard set is never derived from one safety data sheet, and aggregate register percentages are never presented as a harmonized classification.
Discharge limits carry instrument, section, jurisdiction and the material they apply to, for example mercury 1 mg/kg and cadmium 3 mg/kg dry weight, maximum, in stock barite under 40 CFR 435.13 (US offshore). US rules apply to US waters, OSPAR, UK and Norway rules to the North-East Atlantic, and the jurisdiction is always named. All offshore discharge rules are written with the same elements.
Units, Conversions and Calculated Values#
Quantities are written in oilfield units first with SI in brackets, such as lb/bbl (kg/m3), lb/gal (sg) and degF (degC), and converted with fixed factors.
The table below lists the fixed factors used on every page.
| Quantity | Oilfield unit | SI equivalent |
|---|---|---|
| Dose | 1 lb/bbl (kg/m3) | 2.853 kg/m3 |
| Mud weight | 1 lb/gal | 119.83 kg/m3 |
| Mud weight | SG 1.00 | 8.345 lb/gal |
| Volume | 1 bbl (42 US gal) | 0.1589873 m3 |
| Pressure | 1 psi | 6.894757 kPa |
| Yield point and gel strength | 1 lbf/100 ft2 | 0.4788 Pa |
| Temperature | degF | subtract 32, then divide by 1.8 for degC |
The figure of 8.33 lb/gal per SG appears only when it is labeled as the IADC field shortcut, and every temperature is written in both degF and degC. Spelling is US throughout, with UK forms only inside quoted source titles.
A number the site computes is labeled "calculated" and its inputs are stated next to it, never presented as a supplier or standard figure. Mud weight units and conversions use only the factors in the table.
How Facts Are Dated and Rechecked#
Each dated fact carries the date its source was checked, and a page is rechecked when the source that governs it changes. Five kinds of change trigger a recheck.
- API Standards Plan revisions
- ISO systematic reviews
- eCFR amendments to 40 CFR 435 and NPDES general permit changes
- OSPAR annual PLONOR updates and OCNS list updates
- USGS Mineral Commodity Summaries, published each February
Prices appear only as dated public-record unit values with the year, and with "e" where the USGS Mineral Commodity Summaries 2026 mark an estimate, never as a quoted market price. Edition and status statements carry a "checked {date}" label, such as API Standards Plan, checked 2026-10-27.
What Stays Off the Page#
A value that cannot be confirmed in a primary source stays off the page until it can be, rather than appearing hedged as "reportedly" or "some sources say".
Four kinds of statement stay off the page.
- Unconfirmed values
- Market sizes stated as fact, because a market size appears only as a named analyst estimate with publisher and year, and drilling fluid and drilling fluid additive estimates are never merged
- Company rankings and recommendations
- Quoted market prices
Methodology and the Editorial Policy#
This page explains how figures are checked; the editorial policy sets out the site's independence, how quote and service requests are disclosed, and how corrections are made.
Errors in a figure are reported to editorial@drillingfluidadditives.com with the page and the source.
The site sells no product, and no company pays to be listed or ranked. Independence, request disclosure and corrections are set out in the editorial policy. The site is funded by forwarding the quote and service requests readers send.
Completion and production chemistry is a separate field, so its figures are not checked here.
Who writes the pages#
Pages carry the byline Drilling Fluid Additives Editorial Team, and no page names an individual author or claims an outside expert review.
The publisher behind the byline is the site itself, described under about DrillingFluidAdditives.com.