Chemical Compatibility Worksheet Template by Use Condition

What is a chemical compatibility worksheet for, and when do you use it?

A chemical compatibility worksheet is a form, with a matching register, that a technical service engineer, application engineer or process engineer fills in to decide whether a named product can share a system with what it meets there. It covers three kinds of combination: the chemicals dosed or stored alongside the product, the wetted metals, elastomers, plastics and coatings it touches, and the residue the previous product leaves at changeover.

Use the worksheet before a new product goes into an existing system, before a material change such as a new gasket or pump seal, before a product switch, and whenever a customer asks whether two products can be used together. The worksheet is filled in before anything is mixed or installed, and it is kept with the system record afterwards.

A safety data sheet is the starting point, not the answer. US OSHA requires section 10 of every safety data sheet to cover stability and reactivity, including conditions to avoid and incompatible materials (OSHA, 29 CFR 1910.1200 Appendix D). EU guidance describes the section 10.5 list as families of substances or mixtures, "such as water, air, acids, bases, oxidising agents", with which the product could react to produce a hazardous situation (ECHA, 2020, section 10.5). Neither list says whether a gasket swells at your temperature or how long your residue stays in the line. The worksheet records those conditions. The editable Word worksheet, an Excel register and a CSV of the register columns are at the end of this page.

Which sections and columns does the chemical compatibility worksheet have?

The chemical compatibility worksheet has six sections, and each column records one condition or one ground for a verdict. The table below previews every column and decides whether a combination can be called compatible, only conditionally compatible pending a test, or incompatible. Example values are illustrative.

The key row is the criterion and limit in section 1: it is written before any chart or test value is read, so the verdict in section 3 cannot be bent to fit the data. A deciding value without its test conditions in section 3 cannot support a compatible verdict.

The Word worksheet holds the six sections for one assessment, with space for every combination. The Excel register holds one row per combination with the same columns, so that assessments for many systems can be filtered by product, material or verdict, and the open items in section 6 can be tracked to closure by owner and date.

How do you fix compatibility criteria before reading chart values?

You fix compatibility criteria before reading chart values by writing, for each axis of the worksheet, the property that decides compatibility, its limit and the source of that limit, and only then collecting values. Criteria chosen after the data are seen tend to move toward the data.

Each axis has its own kind of criterion. For a coexisting chemical, the deciding properties are reaction, gas release, heat, precipitation, phase separation or loss of function. For a wetted metal, the usual criterion is a corrosion rate from a mass loss test; ASTM G31-21(2025) describes the factors that influence laboratory immersion corrosion tests, particularly mass loss tests, including the calculation of corrosion rates (ASTM G31, 2025). For an elastomer, it is volume, mass or hardness change after immersion, as measured by ASTM D471-16a(2021) or ISO 1817:2026 (ASTM D471, 2021; ISO, 2026). For a plastic, ASTM D543-21 provides for reporting changes in weight, dimensions, appearance, color, strength and other mechanical properties (ASTM D543, 2021). For a residue at changeover, the criteria are miscibility and the residual share the system can tolerate.

Take each limit from the customer's specification or the manufacturer's written statement where one exists. Where neither exists, use a published criterion and mark it typical, with its source. Write the limit as a number with a unit and a sign: a 10% volume swell limit for an elastomer is a different criterion from a 10% shrink limit (illustrative). Where the two sides can meet undiluted, as in a shared dosing line, a common bund or a spill, add the neat contact as its own combination beside the in-use one.

Which composition and material grade details does a compatibility worksheet need?

A compatibility worksheet needs each product's components by chemical name, CAS number and concentration band, and each wetted material by its grade, because a trade name or a material family does not fix what the verdict rests on. Two products with the same trade category can differ in the one component that reacts, and two EPDM seals can differ in the cure system that decides their resistance.

Take components from section 3 of the safety data sheet for the customer's jurisdiction. Under US OSHA rules, section 3 of a mixture's safety data sheet gives the chemical name, CAS number or other unique identifier, and the concentration or concentration range of ingredients classified as health hazards, and concentration ranges may be used where a trade secret is claimed or batches vary (OSHA, 29 CFR 1910.1200 Appendix D). The worksheet therefore records a band, not an exact share, and marks whether each row is publicly disclosed or internal.

Take incompatibilities from section 10 of the same sheet, with its revision date. EU guidance notes that a long list of incompatible materials can dilute the message and that substance classes such as "aromatic solvents" may be used instead of individual substances (ECHA, 2020, section 10.5). A class entry on a safety data sheet is a prompt to check, not a verdict for your pairing.

For materials, record the alloy designation, the elastomer type and compound, the polymer type or the coating system, and the record it comes from: a drawing, a parts list or a supplier certificate. A material known only by its family is judged on the weakest common grade of that family and marked grade unconfirmed.

How do you record each compatibility verdict and its grounds?

You record each compatibility verdict by writing the deciding value against its limit, the conditions the value was measured at beside the customer's conditions, the source kind and date, the verdict and its confidence on one row per combination. One overall verdict for the system follows from the rows, not the other way round.

The verdict has three values. Compatible means the evidence covers the combination's concentration, temperature and contact time and the value meets the limit. Conditionally compatible means the evidence is thinner than the conditions, or the value meets the limit only within a bound, and the condition is a confirmation test or an operating limit. Incompatible means the value fails the limit, or the safety data sheet lists the pairing as incompatible and nothing narrower overrides it. Place any combination that can give off gas, heat or a hazardous product first in the section, with the separation it needs.

Mark every value from a public chart, a handbook or another site's experience as typical, with the conditions it was measured at. Test conditions often differ from service: ASTM D471-16a(2021) states that its accelerated test "may not give any direct correlation with actual part performance, since service conditions vary too widely" (ASTM D471, 2021). ASTM G31-21(2025) states that accelerated corrosion tests "give indicative results only, or may even be entirely misleading" (ASTM G31, 2025). Where the value was measured below the customer's concentration, temperature or contact time, carry that gap into the confidence column, so that a reader can see why a passing value still gives only a conditional verdict.

How does a compatibility worksheet record a conditional verdict and its limits?

A compatibility worksheet records a conditional verdict by giving it bounds the site can hold, a sign the site can see, a place and frequency to look, and a reading at which the site stops. A conditional verdict without those four entries reads as approval, and the condition is lost at the first shift change.

Write each bound as a value with its basis: a maximum temperature, a maximum concentration, a maximum contact time, or a flushing step at changeover. Then name the early sign in the customer's own process: haze, deposits, foaming, discoloration, swelling, weight loss, or a shift in pH or conductivity. Give the observation point, such as a sight glass, a sample valve or a gasket inspection at the next shutdown, and the frequency. Finish with the stop reading, written as a number where one exists (illustrative: stop if pH moves more than 1 unit from the fresh-mix value).

Changeover residues need their own bound. A conversion guide from a fluid supplier notes that "a small remaining quantity of mineral oil can impair the fire resistance and stability" of a water-based hydraulic fluid filled as a replacement (ExxonMobil, 2023). The worksheet records the residual share the new product tolerates and the flush that keeps the system below it. Where no residual share is on record, judge the pairing across mixing ratios from a trace to equal parts.

For each incompatible combination the customer can avoid, record the measure that keeps the two apart: dedicated dosing points, lines and tanks, a flush between products, or segregated storage. Where no combination is conditional or avoidably incompatible, the section says so in one sentence.

Which confirmation tests settle a conditional compatibility verdict?

Confirmation tests settle a conditional compatibility verdict when their conditions match the customer's and their acceptance criterion is the one fixed in section 1 before any value was read. Each test row names the method, the conditions, the duration, the acceptance criterion, the sample, the owner and the due date.

Match the test to the axis. For metals, a coupon immersion test designed with ASTM G31-21(2025), which covers test solution composition, temperature, gas sparging, fluid motion, solution volume and duration (ASTM G31, 2025). For elastomers, an immersion test by ASTM D471-16a(2021) or ISO 1817:2026 (ASTM D471, 2021; ISO, 2026). For plastics, ASTM D543-21 or ISO 175:2010; ASTM notes that the two address the same subject but "the results cannot be directly compared" (ASTM D543, 2021, Note 2). For two chemicals or a changeover residue, a bottle compatibility test at the ratios found in the system.

A bottle mixing test of two chemicals that can react is a hazardous step. Before mixing, read sections 7 and 10 of both safety data sheets for incompatibilities and conditions to avoid, start with small quantities, and work under the site's written procedure. In the US, an employer whose laboratory uses hazardous chemicals must develop and carry out a written Chemical Hygiene Plan (OSHA, 29 CFR 1910.1450(e)(1)); elsewhere, follow the equivalent rule for the jurisdiction. ASTM states that its guides do not address all safety concerns and that users must establish safety practices before use (ASTM G31, 2025). NOAA's chemical reactivity tool predicts hazards from mixing all possible pairs in a virtual mixture (NOAA, 2013), so run it before any bench mixing, not instead of it. Name the one test that decides the overall verdict.

Chemical compatibility worksheet filled in (illustrative)

A chemical compatibility worksheet filled in for one change shows how the six sections connect: the criterion fixed in section 1 decides the verdict in section 3, and the conditional verdict creates the limits in section 4 and the test in section 5. Every product, value and date below is illustrative.

A water treatment supplier proposes Product A, an acidic cleaner with phosphoric acid (CAS 7664-38-2) at 10 to 20% from its safety data sheet section 3, for a circuit that also receives Biocide B and has EPDM gaskets and 316L stainless steel pipe (illustrative). The worksheet reads as follows in this illustrative case.

The key row is the neat contact in the shared bund: it is incompatible even though the in-use row is only conditional, so the overall verdict for this illustrative system waits on separation and on the bottle test. Section 6 then lists the unconfirmed gasket compound and names the maintenance planner as the person who can settle it (illustrative).

When does a chemical compatibility worksheet need a new assessment?

A chemical compatibility worksheet needs a new assessment whenever a condition it was judged at changes: an added coexisting chemical, a material change, a higher temperature, a changed dose or contact time, or a revised safety data sheet for either side. The verdicts hold only for the conditions written in section 1.

Record the triggers in section 6, next to the open items, so that whoever changes the process sees which verdicts it reopens. A new gasket compound reopens every row on the wetted material axis that the gasket touches. A new cleaning step at a higher temperature reopens every row whose temperature range it exceeds, because the evidence behind a compatible verdict was read at the old range. A safety data sheet revision reopens section 2: compare the new section 3 components and section 10 incompatibilities with the rows on file, and note the revision date on the worksheet.

Changes on the supplier side count as much as changes in the plant. A product reformulated under the same trade name may carry a different component band; compare section 3 of each new safety data sheet, which lists hazardous ingredients with their concentrations or concentration ranges (OSHA, 29 CFR 1910.1200 Appendix D), with the rows on file. Set a review date on the worksheet even when nothing is known to have changed, so that an unnoticed change is caught at the next review rather than at the next failure.

A test result that arrives after the worksheet was issued also triggers a new version: the conditional row becomes compatible or incompatible, and the overall verdict is recomputed from the rows.

Where a chemical compatibility worksheet does not fit

A chemical compatibility worksheet does not fit a choice among candidate products, a failure that has already happened, or the design of a formulation. Each of those questions needs its own document, and forcing it into a worksheet hides the decision it really asks for.

Choosing among candidates is a selection: compatibility is one screening check inside it, alongside performance, supply and cost factors that the worksheet has no column for. Damage, a reaction or a quality failure that has already occurred needs containment and a cause; the worksheet records expected behavior under stated conditions and cannot show what caused an observed failure. Compatibility between the components of a formulation under design is a formulation question, with its own stability and performance tests.

The worksheet also does not replace a hazard review. A reactivity tool and a safety data sheet flag pairings that can react; they do not size a relief system or a bund. The worksheet is not a substitute for the jurisdiction's process safety rules where large quantities of reactive chemicals are stored or mixed.

Finally, the worksheet is only as good as its inputs. A combination whose contact condition, composition or grade stays unknown keeps its row, marked unconfirmed, and is judged at most conditionally compatible. Where ASTM D543-21 notes that short-time test data are "of interest only in eliminating the most unsuitable materials" for continuous immersion (ASTM D543, 2021), the worksheet should treat a short test the same way.

Chemical compatibility worksheet checklist

A chemical compatibility worksheet checklist confirms, before the worksheet is issued, that every verdict can be traced to a condition, a criterion and a source.

• The question is written in one sentence, naming the product and the system.

• Every combination is on its axis: coexisting chemical, wetted material or residue at changeover.

• Each combination has a contact point, a concentration in %, a temperature range in °C including start-up and cleaning extremes, and a contact time in h.

• Neat contact in shared lines, bunds or spills has its own row.

• Each axis has a criterion, a limit with a unit and sign, and a source, written before any value was read.

• Each product is listed by component, CAS number and concentration band, with the safety data sheet revision date.

• Each wetted material is listed by grade, with the record it comes from.

• Each verdict row shows the deciding value, its test conditions beside the customer's conditions, the source kind and date, and the typical marker.

• Combinations that can give off gas, heat or a hazardous product stand first.

• Each conditional verdict has bounds, a sign to watch, an observation point and frequency, and a stop reading.

• Each incompatible combination the customer can avoid has a separation measure.

• Each confirmation test has a method, conditions, duration, acceptance criterion, owner and due date, and mixing tests name the safety data sheet sections and the site procedure.

• Open items and the changes that call for a new assessment are listed with the person who can settle them.

Lubinpla's compatibility assessment works along the same axes, coexisting chemicals, wetted materials and residue at changeover, judging each combination from your own documents and site history and returning one cited document for your review.