Painting and Decorating (C-33) · Lesson 1 of 6

VOC Content: Reading the CALGreen Coating Limits

"VOC Content: Reading the CALGreen Coating Limits" is lesson 1 of 6 in the Painting and Decorating (C-33) Learning Hub. It opens with "The Limit Is Printed in the Building Code" and works through 5 short steps, then a worked example you can check yourself against.

Open the free trialSee pricing

One-time purchase, no subscription. Law & Business included.

Steps in this lesson

  1. The Limit Is Printed in the Building Code
  2. What "Less Water and Less Exempt Compounds" Means
  3. Pick the Category First
  4. The Arithmetic
  5. Caulks, Sealants and Adhesives Have Their Own Tables

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Write the basis from the table heading" through "Keep the proof".

What you'll be able to do

  • Explain the main idea of "VOC Content: Reading the CALGreen Coating Limits" in plain language you can use on the exam.
  • Apply this step with confidence: "Pick the Category First".
  • Apply this step with confidence: "The Arithmetic".
  • Apply this step with confidence: "Caulks, Sealants and Adhesives Have Their Own Tables".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
VOC Content: CALGreen Coating LimitsVOC (g/L) = grams of VOC ÷ (L coating − L water − L exempt)Table heading: "Grams of VOC per Liter of Coating, Less Water and Less Exempt Compounds"Footnote 1: Low solids coatings (120) count water and exempt compoundsA: FLAT LATEX20 g VOC, 0.500 L water1.000 − 0.500 = 0.500 L20 ÷ 0.500 = 40 g/LLimit: Flat 50PASSB: SEMI-GLOSS ENAMEL70 g VOC, 0.520 L water1.000 − 0.520 = 0.480 L70 ÷ 0.480 = 145.8 g/LLimit: Nonflat-high gloss 150PASSC: PRIMER-SEALER140 g VOC, 0.470 L water1.000 − 0.470 = 0.530 L140 ÷ 0.530 = 264.2 g/LLimit: Primer/sealer 100FAILTable 4.504.3 limits (g/L)Flat 50 | Nonflat 100 | Nonflat-high gloss 150 | Primers, sealers, undercoaters 100Rust preventative 250 | Industrial maintenance 250 | Stains 250 | Wood coatings 275Stricter local air-district limits override the table (§4.504.2.2)Source: 2025 CALGreen Table 4.504.3 (also Table 5.504.4.3)CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: The Limit Is Printed in the Building Code

VOCs (volatile organic compounds) are the solvents that evaporate out of a coating as it dries. The 2025 California Green Building Standards Code (CALGreen) sets the limit for the paints a painter applies: 2025 CALGreen §4.504.2.2 (residential) and §5.504.4.3 (nonresidential) both say architectural paints and coatings must meet the VOC limits in Table 4.504.3 or Table 5.504.4.3, "unless more stringent local limits apply." So the table is the floor, and a stricter air-district rule can override it. Compliance is shown, if the enforcing agency asks, by the manufacturer's product specification or by field verification of the on-site product containers (§4.504.2.4, §5.504.4.3.2), so keep the data sheet and leave the labels on the cans.

Step 2: What "Less Water and Less Exempt Compounds" Means

Every coating table in the Code is headed "Grams of VOC per Liter of Coating, Less Water and Less Exempt Compounds." In plain words: take the grams of VOC and divide by the liters of coating after the volume of water and the volume of exempt compounds has been taken out. Water adds volume but no VOC, so for a waterborne paint this figure is always higher than grams per whole liter of wet paint. One category is different: footnote 1 on Table 4.504.3 says Low solids coatings (limit 120) are measured in grams of VOC per liter of coating including water and including exempt compounds. (The Code prints the basis in words; the arithmetic in Step 4 is just that wording written out.)

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

More lessons for this trade

Browse all lesson previews

Ready to practice for real?

Try the real classroom free, no sign-up, or get the full course for your trade.

Open the free trialSee pricing

Independent exam preparation. Contractors Classroom is not affiliated with the Contractors State License Board, and no course can guarantee a passing result.