Sampling and testing frequency: how many tests the specification asks for, and when
A road-and-services estimate has one allowance for density testing. The work plan divides the backfill into many separate stages. The coordinator needs to apply the actual frequency rule to those stages before accepting the agency's total.
Read each actual testing-frequency clause and apply its rule to the quantities, locations and sequence it governs. Confirm the interpretation with the agency and authorized technical reviewer before relying on the count. Keep defined lots, days, lifts or areas separate where the rule requires it. A whole-job quantity divided by one convenient number can conceal required tests at individual stages.
Make the test count auditable
- Extract the rule and its basis. Record the current section, clause, adopted reference and exact unit or trigger. Identify combined conditions, minimums and any rounding instruction that applies. Ask about unclear terms such as 'lot' instead of selecting a definition that fits the budget. The specification's actual rule determines the required count.
- Map the governed work. List activities, locations, planned quantities and their defined divisions. Use the schedule to show when the governed work occurs. Apply the reviewed rule to each relevant division, including any minimum or rounding separately where required. Keep the calculation visible so a revised quantity or split can be checked.
- Separate counts with different meanings. Distinguish visits, samples, specimens, individual measurements and reported tests using the actual agency definitions. Add a separately identified planning allowance for possible retests or instructed extra work. That allowance does not replace required initial testing or authorize a different frequency.
- Reconcile as work proceeds. Compare the required count for actual completed work with tests taken and represented locations. Identify cancelled work, changed divisions, additional requirements and gaps. Send missed or disputed testing through the appropriate review process; do not quietly increase next week's total and assume it resolves last week's untested stage.
Let the budget follow the reviewed scope. Compare the agency's price basis with the counted visits and tests, and identify assumptions that need commercial clarification. Keep the count's version and reviewer with the look-ahead entry. A more expensive result is a planning issue to resolve, not a reason to reduce an actual requirement without an authorized change.
Common mistakes
- Rounding the whole job when the rule applies to separate divisions.
- Calling every specimen a separately required test.
- Using a retest allowance to hide a missed initial test.
Checklist
Review a test-frequency calculation
- Current clause, unit and reviewer.
- Defined divisions and planned quantities.
- Visible calculation with actual minimums and rounding.
- Visits, samples and tests distinguished.
- Required versus taken locations reconciled.
Check your understanding
Two lots combine on the programme. Can you automatically halve their test count?
