BPI Insulation Standards 5 — Questions and Answers
Question 1: What is the key advantage of continuous exterior insulation over insulation installed only between framing members?
- It is always less expensive to install
- It eliminates thermal bridging through structural framing (Correct answer)
- It provides better fire resistance
- It is the only method approved by BPI for new construction
Correct answer: It eliminates thermal bridging through structural framing
Continuous exterior insulation wraps the entire wall surface including studs, eliminating the thermal bridging that reduces effective R-value in cavity-only insulation systems.
Question 2: According to BPI protocol, when should an energy auditor recommend replacing existing insulation rather than adding on top of it?
- Whenever the existing insulation is more than 10 years old
- When existing insulation is wet, moldy, pest-infested, or severely settled (Correct answer)
- When the homeowner requests a specific insulation type
- Any time blown-in insulation is already present
Correct answer: When existing insulation is wet, moldy, pest-infested, or severely settled
Existing insulation should be removed and replaced when it is compromised by moisture damage, mold, pest infestation, or significant settling that degrades its thermal performance.
Question 3: What does an 'R-value label' on insulation packaging indicate per FTC regulations?
- The insulation's environmental impact rating
- The thermal resistance of the insulation product as tested under standardized conditions (Correct answer)
- The insulation's air permeance rating
- The maximum temperature at which the insulation can be safely used
Correct answer: The thermal resistance of the insulation product as tested under standardized conditions
The FTC R-value Rule requires insulation manufacturers to disclose the product's thermal resistance (R-value) on packaging, tested per ASTM standards under defined conditions.
Question 4: A crawlspace with vented foundation walls in Climate Zone 5 should be insulated according to BPI by placing insulation where?
- On top of the subfloor from above
- On the underside of the floor joists in the crawlspace (Correct answer)
- On the crawlspace walls to create a conditioned crawlspace
- No insulation is needed in vented crawlspaces
Correct answer: On the underside of the floor joists in the crawlspace
In a vented crawlspace, BPI recommends insulating the underside of the floor joists (floor above) to maintain conditioned space boundaries, though encapsulated crawlspaces are often preferred.
Question 5: Which ASTM standard governs the test method for measuring thermal resistance (R-value) of insulation materials?
- ASTM C518 or ASTM C177 (Correct answer)
- ASTM E779
- ASTM D6226
- ASTM E84
Correct answer: ASTM C518 or ASTM C177
ASTM C518 (heat flow meter) and ASTM C177 (guarded hot plate) are the primary standards for measuring steady-state thermal transmission properties of insulation.
Question 6: What is the recommended indoor relative humidity range to prevent condensation problems within wall insulation assemblies during winter?
- 60–70%
- 30–50% (Correct answer)
- 10–20%
- 55–65%
Correct answer: 30–50%
Maintaining indoor relative humidity between 30–50% during heating season reduces the vapor pressure driving moisture into wall assemblies and helps prevent interstitial condensation.
Question 7: In a BPI energy audit report, which measure is used to quantify the cost-effectiveness of adding insulation to an attic?
- Energy Star rating improvement
- Simple payback period or return on investment (ROI) (Correct answer)
- HERS Index improvement
- Net present value of carbon reduction
Correct answer: Simple payback period or return on investment (ROI)
BPI auditors typically present simple payback period (cost divided by annual energy savings) or ROI to communicate the economic benefit of insulation upgrades to homeowners.
BPI Insulation Standards 5
What is the key advantage of continuous exterior insulation over insulation installed only between framing members?