Floor Flatness Testing in Canada: Industrial Slab Comparison

For Canadian industrial slabs, specify ASTM E1155 FF/FL profiling for random traffic, a contract-defined 10 ft straightedge procedure for flatness only, or Fmin/Profileograph measurement for defined vehicle paths.[1][2][6] Base acceptance on the metric, standard edition, test areas and criteria incorporated into the project documents—not a generic benchmark.[1][2][3]

Choose the test method for the floor’s traffic

ASTM E1155 FF/FL profiling

• Use: Suited to random-traffic slabs, where vehicles are not restricted to designated wheel paths.[1][2]
• Result: Sampled elevations produce statistical overall and local-area results. FF represents surface bumpiness or waviness; FL represents levelness relative to a horizontal plane.[1][2]
• Key limitation: It does not replace continuous Fmin wheel-path measurement for defined traffic.[2]

Manual 10 ft straightedge

• Use: Suited to a contract requiring a conventional flatness-only check rather than statistical FF/FL or defined-path measurement.[6]
• Result: Conspectus describes one sample per 100 ft², oriented parallel, perpendicular or at 45 degrees to the longest construction joint.[6]
• Key limitation: It does not measure levelness and, under that guidance, is not permitted for Very Flat or Super Flat classifications.[6]

Fmin/Profileograph measurement

• Use: Suited to very-narrow-aisle, wire-guided, rail-guided and other defined-traffic vehicle paths.[2]
• Result: A Profileograph continuously measures designated wheel tracks, allowing path-specific defects to be located.[2]
• Key limitation: Fmin is not the statistical FF/FL acceptance system used for random-traffic floors.[2]

Slabs on grade are generally specified with both FF and FL. Elevated slabs are generally specified with FF only because deflection affects levelness, and FL does not apply to sloped or cambered floors.[2][6]

Anchor acceptance to the contract

ASTM E1155, Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers, provides a quantitative method for estimating a floor’s characteristic FF and FL numbers.[1] Higher F-numbers indicate better results for the characteristic measured.[1][2]

The project documents should identify the governing test method, edition and acceptance criteria.[1][2][3] Somero identifies CSA A23.1 as a Canadian F-number standard, while MA Concrete discusses the older CSA A23.1-94 edition; neither cited page establishes the applicable edition or Canadian requirements for a particular project.[2][3] Verify the edition and clauses incorporated into the contract rather than treating example FF/FL values as universal Canadian limits.[1][3]

Agree test areas, exclusions, timing and run layouts

Before placement, define the complete test surface, named test sections, exclusions and sample measurement lines or test runs used in the ASTM E1155 framework.[1]

• Test areas: Identify each test section and show construction joints and agreed exclusions on a drawing or schedule.[1][6]
• Section boundaries: The ACI resource states an ASTM E1155 test section may not be less than 8 ft on a side or contain less than 320 ft². Conspectus also says a sample panel should not cross a construction joint.[1][6]
• Run layout: Record planned run coordinates and the line lengths, measurement intervals and sampling density required by the adopted method and edition. Somero attributes to ASTM E1155 measurement lines of at least 11 ft, elevations at 1 ft intervals and at least 34 elevation measurements per 1,000 ft².[2]
• Timing: The cited guidance calls for FF/FL testing within 72 hours after finishing because curing, shrinkage and curling can change the profile; prompt results can also inform later placements.[1][2][3][6]

Exact boundaries, coordinates and exclusions are project-specific and should not be left until after results are available.[1]

Require a report that locates every result

The acceptance report should carry the approved test plan through to the results. Require:

• Location records: Identifiers or drawings for the test surface, every test section and every measurement run.[1]
• Contract criteria: The applicable Specified Overall FF and FL and Minimum Local FF and FL values beside the results, limited to the characteristics used by the contract.[1][6]
• Complete results: Composite overall FF and FL values, individual run data and results for each properly sampled minimum-local area.[1]
• Located exceptions: Each exception tied to a test section or minimum-local area, with enough detail for review and possible follow-up testing.[1]
• Traceability: The test date and time relative to finishing, adopted method and edition, measurement layout and agreed exclusions.[1][2][3]

Run graphs may show elevation change against distance. A mesh diagram can help evaluate an out-of-specification area and plan further investigation or repair.[1]

Use overall and minimum-local results for acceptance

First compare the test surface’s composite results with the contract’s Specified Overall flatness and levelness values, or SOFF and SOFL. Then compare each properly sampled minimum-local area with its MLFF and MLFL criteria.[1]

One low measurement line is data, not automatically a minimum-local-area failure. The March 2012 correction to the ACI resource clarifies that rejection requires evaluation of a properly sampled minimum-local area.[1] If the overall results meet or exceed SOFF and SOFL and no properly evaluated local area violates MLFF or MLFL, the cited ACI guidance says remediation is unnecessary.[1]

The ACI resource and Conspectus describe Minimum Local values as typically 60% of the Specified Overall values unless otherwise specified.[1][6] Somero’s handbook, by contrast, says Minimum Local numbers are generally set 30%–50% lower than the Specified Overall numbers and recommends no Minimum Local values below FF 13/FL 10.[2] These are guidance, not universal Canadian contract limits; the project’s adopted criteria control.

Resolve the specification before accepting a pass/fail conclusion if it lists only one FF/FL pair, does not distinguish overall from local criteria or treats the lowest run as automatic grounds for rejection.[1]

Separate pass/fail findings from repair decisions

The test report should locate results and state compliance against the adopted criteria. Decisions about additional testing, repair limits, remediation, retesting and payment consequences belong in the contract’s authority structure.[1]

If a minimum-local area fails, additional testing may be needed to establish the repair boundary. If the overall result fails, the response may address the entire test surface or selected areas, followed by retesting.[1] Potential responses include:

• Slab on ground: Grinding, planing, surface repair, retopping, or removal and replacement.[1]
• Suspended slab: Grinding, underlayment or topping.[1]

Localized grinding may not resolve a statistical FF/FL failure on a random-traffic floor. Somero cautions that removing a bump in one direction can create a dip in another; continuous Profileograph data can instead locate wheel-track defects on defined-traffic paths for targeted treatment.[2]

The contract should assign authority for added testing, repair-boundary approval, remedy selection, retesting, acceptance after correction and payment reductions. ACI guidance recommends leaving the remedial method to the Engineer of Record’s project-specific judgment.[1]

Procurement checklist

• Method: State whether the scope uses ASTM E1155 FF/FL, a contract-defined straightedge procedure or Fmin/Profileograph measurement.[1][2][6]
• Acceptance basis: Attach the governing contract clause and adopted standard edition. State separate Specified Overall and Minimum Local values and identify any inapplicable characteristic.[1][2][3][6]
• Test plan: Issue test-surface and section boundaries, joints, exclusions and run layouts before placement.[1][6]
• Timing: State the testing window and the procedure for access or sequencing problems.[1][2][3][6]
• Deliverables: Require located overall, minimum-local and run results, with the contractual basis for each pass/fail finding.[1]
• Decision rule: Do not label one low measurement line a contractual failure unless the adopted regime supports rejection through a properly sampled minimum-local area.[1]
• Post-failure authority: Address added testing, repair boundaries, remediation, retesting and payment consequences separately.[1][2]

What to confirm with each provider

The cited pages do not state Canadian service coverage, prices, quotation structures, turnaround commitments, warranties or cancellation terms. They also do not establish universal Canadian requirements for tester qualifications, instrument calibration evidence, report signatories or record-retention periods. Request these details and supporting documents with each quotation.

References

1. The attached excerpted resource materials have been made available for use (concrete.org)
2. F-Numbers Handbook for Floor Flatness | Somero – Somero (somero.com)
3. Final Floor Requirements | maconcrete – MA Concrete Ltd. (maconcreteltd.com)
6. TECH TIPS www.conspectusinc.com Vol12.10.01 ©2012 Conspectus Inc. Page 1 of 2 (hubspot.net)