Mixed Deck — All BOC Topics Flashcards

Which ASHRAE standard defines conditions for human thermal comfort in occupied spaces?

Answer: ASHRAE Standard 55

ASHRAE 55 specifies the combinations of temperature, humidity, air speed, and other factors that produce acceptable thermal comfort.

In a building's domestic hot water system, what is the purpose of a recirculation loop?

Answer: To ensure hot water is quickly available at fixtures without long wait times

A recirculation loop continuously circulates hot water through the distribution piping so occupants get near-instant hot water at any fixture.

Why is proper ventilation important in maintaining indoor air quality?

Answer: To dilute and remove indoor contaminants

Proper ventilation helps remove indoor pollutants and brings in fresh air, improving overall air quality.

What is the main goal of a root cause analysis after a repeated equipment failure?

Answer: To find the underlying cause so the failure does not happen again

Root cause analysis looks past the symptoms to the underlying cause, so corrective action prevents the failure from coming back.

Under EPA Section 608 rules, the leak rate that triggers mandatory repair for comfort cooling appliances containing 50 pounds or more of ozone-depleting refrigerant is:

Answer: 10%

Comfort cooling appliances must be repaired when the annualized leak rate exceeds 10%, versus 20% for commercial refrigeration and 30% for IPR.

What does 'TDS' stand for in boiler water treatment, and why is it monitored?

Answer: Total Dissolved Solids; to prevent scale and foaming by controlling blowdown

Total Dissolved Solids (TDS) measures the concentration of minerals and impurities in boiler water; high TDS causes scale, foaming, and carryover, controlled through blowdown.

Which water treatment chemical is commonly added to a closed hydronic heating or chilled water loop to prevent internal pipe corrosion?

Answer: Corrosion inhibitor (such as molybdate or nitrite-based treatment)

Closed loop systems use corrosion inhibitors to form a protective film on metal pipe interiors, preventing oxidation and extending system life.

What does a Variable Air Volume (VAV) system do?

Answer: Vary airflow based on space requirements

VAV systems adjust the amount of air delivered to spaces based on cooling or heating needs, improving efficiency.

What is the primary benefit of implementing energy conservation strategies in buildings?

Answer: Reduces energy use and costs

Energy conservation helps reduce operating costs, environmental impact, and improves building efficiency.

What indoor relative humidity range is generally recommended to limit mold growth and dust mites while avoiding overly dry air?

Answer: 30% to 60%

Keeping RH between about 30% and 60% limits microbial growth and dust mites without causing dryness complaints.

What code compliance requirement applies to safety procedures?

Answer: All work must comply with applicable local, state, and national codes

Code compliance is mandatory for all work, ensuring safety, quality, and legal adherence.

Which retrofit typically gives the greatest lighting energy reduction in a warehouse with high-intensity discharge fixtures?

Answer: LED high-bay fixtures with occupancy controls

LED high-bays use far fewer watts than HID and can instantly dim or switch off with occupancy sensors.

What inspection procedure is essential for material selection?

Answer: Systematic inspection following established checklists and standards

Systematic inspections using established checklists and industry standards ensure quality and compliance at every stage.

What is the primary purpose of a heat recovery wheel (enthalpy wheel) in an air handling unit?

Answer: Transfer heat and moisture between exhaust and incoming outdoor air

Enthalpy wheels recover sensible and latent energy from exhaust air to precondition outdoor air.

What code compliance requirement applies to equipment operation?

Answer: All work must comply with applicable local, state, and national codes

Code compliance is mandatory for all work, ensuring safety, quality, and legal adherence.

Which instrument is most appropriate for finding missing insulation and air leaks in a building envelope?

Answer: Infrared thermal imaging camera

Infrared cameras show temperature differences on surfaces that reveal insulation voids and air infiltration.

What is the recommended procedure when a boiler safety relief valve lifts (opens)?

Answer: Identify and correct the cause of overpressure before resuming operation

A lifting safety valve signals a potentially dangerous overpressure condition; the root cause must be found and corrected before safely resuming boiler operation.

How should hazardous conditions be handled during environmental standards work?

Answer: Stop work, secure the area, report the hazard, and follow safety protocols

All hazardous conditions require immediate action: stop work, secure the area, report the hazard, and follow established safety protocols.

Under NFPA 10, stored-pressure dry chemical extinguishers require a hydrostatic test at what interval?

Answer: Every 12 years

Dry chemical stored-pressure extinguishers with steel or aluminum shells are hydrostatically tested every 12 years.

In a BAS, what does a DDC controller stand for?

Answer: Direct Digital Control

DDC stands for Direct Digital Control, where a microprocessor-based controller reads sensor inputs, executes control logic, and drives outputs to regulate building systems.