SHI Risk Assessment & Mitigation 3 — Questions and Answers
Question 1: Before mounting solar collectors on a residential roof, which structural risk assessment step is MOST critical?
- Checking attic insulation R-value
- Verifying roof framing can support added dead load of panels plus snow/wind (Correct answer)
- Confirming roof color matches collector frame
- Testing roof surface temperature with an IR thermometer
Correct answer: Verifying roof framing can support added dead load of panels plus snow/wind
Solar collectors add significant dead load, and roof framing must be assessed to ensure it can support panels plus applicable snow and wind loads without failure.
Question 2: An installer is working on a steep-pitch roof without guardrails. Under OSHA 1926.502, what fall protection measure is required when working at or above 6 feet?
- A spotter standing below to warn of falling objects
- Personal fall arrest system, safety net, or guardrail system (Correct answer)
- Non-slip footwear only
- Completing a safety briefing before starting work
Correct answer: Personal fall arrest system, safety net, or guardrail system
OSHA 1926.502 mandates that workers on roofs 6 feet or more above a lower level must be protected by guardrails, safety nets, or a personal fall arrest system.
Question 3: When running AC wiring from a solar thermal pump controller on a ladder, what electrical risk is specifically associated with aluminum ladders?
- Aluminum corrodes rapidly near copper wiring
- Aluminum conducts electricity, increasing electrocution risk if the ladder contacts a live wire (Correct answer)
- Aluminum ladders cannot support the weight of electrical tools
- Aluminum causes static discharge near solar collectors
Correct answer: Aluminum conducts electricity, increasing electrocution risk if the ladder contacts a live wire
Aluminum ladders are electrically conductive; contact with live wiring can complete a circuit through the installer, causing electrocution.
Question 4: What is the risk of not installing a check valve on the collector supply line of a thermosiphon or pump-driven solar system?
- Overpressure in the storage tank during daylight
- Reverse thermosiphoning at night, cooling the storage tank (Correct answer)
- Reduced freeze protection during winter
- Increased pump cavitation at startup
Correct answer: Reverse thermosiphoning at night, cooling the storage tank
Without a check valve, cooled fluid in the collectors can thermosiphon backward at night, drawing heat out of the storage tank and wasting stored energy.
Question 5: A solar thermal installer suspects roof decking is deteriorating under existing shingles. What is the BEST risk-mitigation step before penetrating the roof for collector mounting?
- Proceed quickly so the roof is not exposed to weather for long
- Probe suspect areas and consult a structural engineer or roofer before mounting (Correct answer)
- Apply roof sealant around all planned penetrations first
- Use lighter mounting hardware to reduce load
Correct answer: Probe suspect areas and consult a structural engineer or roofer before mounting
Mounting on compromised decking risks fastener pull-out under collector load or wind uplift; a qualified evaluation must occur before any penetrations are made.
Question 6: During a site visit, an installer finds the main electrical panel is already at full capacity. What risk does adding a pump controller circuit create?
- Radio-frequency interference with the controller display
- Overloading the panel, creating a fire hazard from overloaded breakers (Correct answer)
- Reduced pump motor lifespan from voltage fluctuation
- Voiding the solar collector manufacturer warranty
Correct answer: Overloading the panel, creating a fire hazard from overloaded breakers
Adding circuits to an already full panel can overload the service, creating a fire risk; a panel upgrade or load audit by a licensed electrician is required.
Question 7: Why is it important to wear UV-protective sunglasses when handling unglazed or glazed flat-plate collectors during outdoor installation?
- Glare from the absorber coating can permanently damage unprotected eyes
- Glycol vapor near collectors causes eye irritation in sunlight
- UV from reflected sunlight can cause accelerated cataract formation
- Both A and C are valid risks (Correct answer)
Correct answer: Both A and C are valid risks
Collectors concentrate and reflect intense UV and visible light; both direct glare causing retinal damage and long-term UV exposure increasing cataract risk are real hazards.
SHI Risk Assessment & Mitigation 3
Before mounting solar collectors on a residential roof, which structural risk assessment step is MOST critical?