Lesson 14: Inspections, Tests, and Course Review

Reading

Thirteen lessons have taught what the 2021 IECC commercial provisions require. Two things prove that a finished building meets them. Inspections say who looks, at what point, and what must stay uncovered until they do. Tests and verifications say how a tight envelope, tight ducts, working controls and commissioned equipment are shown rather than assumed. Section C105 sets the inspections, and Sections C402.5, C403.12, C408 and C401.3 set the tests, verifications and paperwork. Local adoption governs: Lesson 1's dated check found that Houston enforces the 2021 IECC with Houston amendments, so confirm the adopted edition and any local test rule before you write a correction. This lesson teaches the inspections and tests, then reviews the whole course.

The six inspections (C105.2)

Section C105.2 names six inspections, made by the code official, a designated agent or an approved agency once the permit holder gives notice. Footing and foundation insulation (C105.2.1) checks the insulation's R-value, location, thickness, depth of burial and protection. Thermal envelope (C105.2.2) checks insulation type, R-values and location, fenestration U-factor, SHGC and VT, and that air leakage controls are properly installed. Plumbing (C105.2.3) checks pipe insulation and its protection, controls and heat traps. Mechanical (C105.2.4) checks equipment type and size, controls, insulation and R-values, system and damper air leakage, fan efficiency, energy recovery and the economizer. Electrical (C105.2.5) checks lighting controls, components and meters. The final inspection (C105.2.6) confirms that all required building controls work and that documentation shows the commissioning of Section C408 was done. The code lists the six but does not set a calendar order. The figure shows the order they usually fall in the field, and the reason is practical: an item is inspected while it can still be seen and fixed.

Keeping work open, and what a failure means (C105.1, C105.3 to C105.6)

Permitted work stays visible and accessible until it is approved, and keeping it that way is the permit applicant's duty (C105.1). Neither the code official nor the jurisdiction is liable for the cost of removing or replacing material to allow inspection, so the cost of opening a closed wall lands on the project. Approval after an inspection is never approval of a violation. The permit holder tells the code official when work is ready and provides access and means for inspection (C105.5). Work that fails is corrected and resubmitted for inspection and testing (C105.6), and a building is reinspected wherever the code official finds it necessary (C105.3). The code official may accept reports from third-party agencies that are not affiliated with the design or construction and are approved for qualifications and reliability (C105.4).

Air barrier: verify it or test it (C402.5)

Section C402.5 lets the envelope comply by meeting the air barrier provisions or by passing a test, and a building that complies by testing must still meet the damper, loading dock and vestibule sections (C402.5.7 to C402.5.9). Inside the air barrier path, C402.5.1.2 decides who tests. Group R and I buildings go to enclosure testing of units (C402.5.2), with exceptions only for Zones 2B, 3C and 5C. Other groups go to a whole-building test (C402.5.3), with exceptions for Zones 2B, 3B, 3C and 5C, for buildings larger than 5,000 square feet in Zones 0B, 1, 2A, 4B and 4C, and for buildings from 5,000 to 50,000 square feet in Zones 0A, 3A and 5B. In Houston (Zone 2A) that means a building outside Group R and I that is larger than 5,000 square feet is excepted, and one of 5,000 square feet or less is tested. A building or portion that does not complete testing meets the materials path (0.004 cfm per square foot or less at 75 Pa, C402.5.1.3) or the assemblies path (0.04 or less, C402.5.1.4), and also the verification in C402.5.1.5. There the code official, a registered design professional or an approved agency reviews the drawings and inspects the air barrier during construction while it can still be reached and repaired. If a design professional or agency did the inspecting, a final commissioning report listing deficiencies and corrections goes to the owner and the code official. These exceptions interlock, so ask the code official which path a project is using.

Air leakage test numbers (C402.5.2 and C402.5.3)

A dwelling or sleeping unit is tested separately with an unguarded blower door at 50 Pa (0.2 inch water gauge) and may leak no more than 0.30 cfm per square foot of unit enclosure area. The building result is the average of the unit results weighted by enclosure area. With fewer than eight units, every unit is tested. With eight or more, the greater of seven units or 20 percent is tested, including a top-floor unit, a ground-floor unit and the unit with the largest enclosure, and each tested unit over the limit adds two more units of mixed type and location (C402.5.2). A whole-building test is limited to 0.40 cfm per square foot of envelope area at 75 Pa (0.3 inch water gauge). A designer may instead test portions and area-weight the results, but the portions must include every story with any space directly under a roof, every story with an entrance, exposed floor or loading dock or that is below grade, and representative above-grade sections totaling at least 25 percent of the wall area around the remaining conditioned space. A result over 0.40 and not over 0.60 is handled by a diagnostic evaluation with smoke tracer or infrared imaging while the building is pressurized, a visual inspection, sealing of the leaks that can be sealed without destroying existing components, and an extra report to the code official and owner. That is deemed to comply (C402.5.3). Window and door leakage is a different kind of check: a lab tests it and the maker labels it (Table C402.5.4), so in the field it is read from the label.

Worked example. A Group B clinic in Houston (Zone 2A) is 4,200 square feet, which is not larger than 5,000, so it is tested unless it takes the materials or assemblies path. Its envelope area is 11,500 square feet, so the limit is 0.40 x 11,500 = 4,600 cfm at 75 Pa. A reading of 4,000 cfm is 0.35 and passes. A reading of 5,750 cfm is 0.50, over 0.40 but not over 0.60, so the diagnostic route applies. A reading of 7,200 cfm is 0.63, over 0.60, so the leaks are sealed and the building is retested. For a four-story R-2 building, 30 units means 20 percent is 6, which is less than 7, so 7 units are tested. With 45 units, 20 percent is 9, so 9 are tested.

Duct leakage tests (C403.12.2)

Ducts are built as the International Mechanical Code says, and what must be sealed or tested depends on the design static pressure, which the drawings must show. At 2 inches w.g. or less, joints and seams are fastened and sealed with welds, gaskets, mastics, mastic-plus-fabric systems or tapes used as the maker directs (C403.12.2.1). Above 2 and below 3 inches, ducts are insulated and sealed as C403.12.1 requires (C403.12.2.2). At 3 inches w.g. or more, the duct is also leak tested with the SMACNA duct leakage manual and must show a leakage class CL of 4.0 or less, worked out from the measured leakage and the test pressure. Documentation must show that representative sections totaling at least 25 percent of the duct area were tested and that every tested section passed (C403.12.2.3). The mechanical inspection also verifies system and damper air leakage (C105.2.4). Most duct in small commercial buildings is low pressure, so the usual field check is a sealed joint, and a test is expected on the high-pressure part of a large system. Example: a Group B building has 4,800 square feet of duct designed for 3.5 inches w.g. At 25 percent, sections totaling 1,200 square feet are tested, and each must reach CL 4.0 or less.

Commissioning and functional tests (C408.2)

Before the final mechanical and plumbing inspections, a registered design professional or approved agency provides evidence that mechanical and service water-heating systems were commissioned (C408.2). Two exceptions apply: buildings whose total capacity is under 480,000 Btu/h of cooling and under 600,000 Btu/h of combined service water and space heating, and economizer systems that serve individual dwelling or sleeping units. Both totals must be under their limits, so a clinic with 300,000 Btu/h of cooling and 400,000 Btu/h of heating is exempt, and adding 200,000 Btu/h of cooling removes the exemption. A commissioning plan comes first (C408.2.1). Air systems and hydronic coils are balanced, and discharge dampers may not be used to balance constant-volume fans or variable-volume fans with motors of 10 hp and larger (C408.2.2.1). Functional performance tests then show that equipment works in every mode of the sequence of operation, at full and part load, in backup mode, in its alarms and on loss and restoration of power (C408.2.3.1). One exception covers unitary or packaged equipment in the Section C403.3.2 tables that does not need a supply air economizer. Controls and their sequences are tested (C408.2.3.2), and air economizers get their own functional test (C408.2.3.3).

The results go in a certified Preliminary Commissioning Report with mechanical and water heating findings in separate sections. It carries the completed checklist, any deficiencies not yet corrected, the tests deferred for climate and the conditions they need, the results, and the procedures with measurable pass criteria (C408.2.4). A building is not acceptable for final inspection until the code official has received that report (C408.2.4.1). The balancing report and the Final Commissioning Report reach the owner within 90 days of the certificate of occupancy, and deferred climate tests are the one exception to the final report's content (C408.2.5).

Lighting controls functional tests (C408.3)

Before a building passes final inspection, evidence must show that the automatic lighting controls were tested and are calibrated, adjusted and programmed (C408.3.1). For occupant sensors, the tester certifies location and aim. With seven or fewer sensors each is tested. With more, each unique combination of sensor type and space geometry is tested at not less than 10 percent, never fewer than one, and if 30 percent or more of the tested sensors fail, all the remaining identical sensors are tested (C408.3.1.1). Time switches are checked for correct weekday, weekend and holiday schedules, the date and time, battery backup, an override limit of no more than 2 hours, and occupied and unoccupied behavior (C408.3.1.2). Daylight controls are checked for location, calibration, response to daylight, and calibration access limited to authorized people (C408.3.1.3). Example: 60 sensors in three combinations of 30, 20 and 10 means at least 3 + 2 + 1 = 6 are tested. If 1 of the 3 tested in the group of 30 fails, that is 33 percent, so the other 27 in that group are tested. Lighting drawings, an operation and maintenance manual and the test report reach the owner within 90 days of the certificate of occupancy (C408.3.2).

Approval and closeout (C106, C401.3, C103.6)

When the prescribed tests and inspections show that the work complies in all respects, the code official issues a notice of approval (C106.1). It can be suspended or revoked in writing if it was issued in error or on incorrect information (C106.2). A permanent thermal envelope certificate is posted in the equipment space, a utility room or another approved place, and it lists insulation R-values, fenestration U-factors and SHGC, and the results of any envelope air leakage testing (C401.3). Within 90 days of the certificate of occupancy the owner also receives record documents and one compliance document that names the code edition used and the lighting compliance path (C103.6).

Course review

The review walks the five modules in order and repeats the numbers used most often. It teaches nothing new, and every value carries the hedges of its lesson. Where a lesson said to check the adopted code, do the same here.

Module 1: Administration and Compliance (Lessons 1 and 2)

Every job starts with which code binds and which route the design takes. Lesson 1's dated check (September 29, 2026) found that the Texas statewide commercial energy code is the 2015 IECC, effective November 1, 2016, with rulemaking on the 2024 IECC expected in 2026, and that Houston enforces the 2021 IECC with Houston amendments from early January 2024. The amendments were not read, so request them. Lesson 2 supplied the zone, the definitions and the labels.

Module 2: Building Envelope (Lessons 3 to 5)

Lesson 3 gave the Zone 2 insulation values, Lesson 4 limited and rated the glass, and Lesson 5 sealed the shell. Which buildings must test for air leakage in Zone 2A depends on the interlocking exceptions above, so ask the code official which path is in use.

Module 3: Mechanical and Water Heating (Lessons 6 to 8)

Lessons 6 and 7 sized, controlled and sealed the HVAC system, and Lesson 8 kept hot water from wasting energy. Equipment efficiencies are pointers to Tables C403.3.2 and C404.2, so compare the nameplate with the schedule. Water temperature at a public lavatory is a plumbing code matter, so check the adopted plumbing code.

Module 4: Lighting and Electrical Power (Lessons 9 to 11)

Lesson 9 controlled the lights, Lesson 10 capped their power and Lesson 11 covered the rest of the electrical rules and the credit tables. Every count starts from the drawings and the luminaire schedule, and a claim with no paper trail is not a credit.

Module 5: Performance, Commissioning, Existing Buildings, and Review (Lessons 12 to 14)

Lesson 12 covered the simulation path and commissioning, Lesson 13 the rules for work on buildings that already stand, and this lesson gathered the inspections and tests that prove all of it. Chapter 5 is the part most used on GCHS rehab jobs: sort the work into an addition, alteration, repair or change of occupancy first.

The practice exam

The practice exam is the next step. It draws 60 questions, weighted by each topic area's share of the question bank, with a 120-minute time limit. It is a practice tool GCHS built for its own staff development. On an actual project, the locally adopted code, not this course, governs.

Practice questions

Glossary

Blower door test

A fan test that pressurizes or depressurizes a building or unit to measure air leakage. Units are tested at 50 Pa and whole buildings at 75 Pa (IECC C402.5.2, C402.5.3).

Envelope performance verification

The review of drawings and the inspection of the continuous air barrier during construction, while it can still be repaired, used where the building does not test (C402.5.1.5).

Diagnostic evaluation

A smoke tracer or infrared check of a pressurized building, with sealing and an extra report, allowed when a whole-building result is over 0.40 and not over 0.60 cfm per square foot (C402.5.3).

Leakage class (CL)

The rating that a leak test of high-pressure duct must reach, 4.0 or less, on sections totaling at least 25 percent of the duct area (C403.12.2.3).

Functional performance test

A test that shows equipment and controls operate in every mode of the sequence of operation, at full and part load, as the plans say (C408.2.3).

Preliminary Commissioning Report

The certified report of commissioning results that the code official must receive before a building is acceptable for final inspection (C408.2.4, C408.2.4.1).

Thermal envelope certificate

The permanent certificate posted in the equipment space or another approved place. It lists R-values, fenestration ratings and any air leakage test results (C401.3).

Notice of approval

The approval a code official issues after the prescribed tests and inspections show the work complies. It can be revoked in writing if issued in error (C106.1, C106.2).