HVAC Unit 34 Indoor Air Quality Study Guide

What is the first step in mold cleanup?

Remove the source of the moisture as quickly as possible.

How small can a HEPA filter down to?

20-30 micons.

What is the maximum allowable concentration of carbon monoxide for short term exposure in a living area according to ASHRAE and exposure in any 8 hour period according to federal law?

9 ppm (parts per million) ASHRAE 50 ppm Federal law

What controls a humidifier?

A humidistat controls the motor and heating elements in the humidifier.

What is the difference between absorption and adsorption?

Absorption is the process of one substance being absorbed by another. Adsorption is the process of a thin film of the liquid or gas adhering to the surface of a solid substance.

Why can oversized air conditioning cause mold.

Air conditioning may not run long enough periods to remove sufficient humidity if the system is oversized. It may turn off with excess humidity still in the air.

What device is used to increase the amount of water in a room?

An evaporative humidifier.

What is the recommended relative humidity for a home?

Between 40-60%

How are dust mites a biological contaminant?

Dust mites can be found everywhere in a home. Their waste products and the disintegration of their bodies leaves very small particulates that mixes with normal household dust. These particulates can be very irritating to people who are sensitive to them.

What are the three steps to controlling indoor air contamination?

Eliminate the source of the contamination Provide adequate ventilation Provide a means to clean the air

T or F: It is easy to tell if there is excess CO in the air due to sour smell it produces.

False- CO is colorless, odorless, tasteless and nonirritating.

T or F: CO poisoning is never fatal

False- concentrations with as little as 800 ppm can cause death can cause death in 2-3 hours. Higher concentrations can cause death within minutes.

T or F: As long as you wear gloves and eyeglasses, it is okay to remove items that contain asbestos or lead.

False- only contractors licensed and equipped for these items can handle and remove them.

T or F: Technicians removing mold need only wear gloves and glasses during cleanup.

False- technicians should wear outer clothing designed for mold removal, including gloves, hat, and respirator.

What are the two most common filters found in homes?

Fiberglass throwaway filters Pleated filters

How does a atomizing humidifier work?

It discharges time water droplets or mist into the air, which evaporate very quickly into the duct airstream or directly into the conditioned space.

Describe Radon and where it comes from?

It is a colorless, odorless and radioactive gas. It comes from the breakdown of uranium that is naturally found in the soil and rocks below our homes.

What is the other name for environmental tobacco smoke (ETS)?

It is also known as secondhand smoke.

Define ventilation.

It is the process of supplying and removing air by natural or mechanical means to and from any space. It removes some of the air with pollutants and dilute the remaining pollutants with acceptable outside air.

What are the four types of air cleaners?

Mechanical Electronic air cleaner Ion generators UV C lights

What is MERV?

Minimum Efficiency Reporting Value. Ratings range from 1 - 20 with the higher numbers providing the most filtering.

What are molds and how do they become a biological contaminant?

Molds are fungus that produce spores that are both smelly and can be hazardous to your health. They can be found in areas that have moisture or high humidity. Molds require food and moisture in order to grow. They can grow almost anywhere.

Why is just cleaning a moldy surface usually not enough?

Molds can penetrate a surface it is feeding on. Bleach or chemicals may be needed to eradicate mold growing on hard surfaces. Carpets must be remove, cleaned and dried. Walls and wood may need to be removed if heavily contaminated.

How does ventilation decrease indoor air pollution?

Outdoor air in sufficient quantities must be brought inside to mix with and dilute the pollution emission, and the indoor air must be vented to the outside to carry out pollutants.

Where do pollutants containing organic chemicals usually come from?

Paints, varnishes, cleaning products, glues, and various fuels.

What is the major contributor of formaldehyde?

Pressed wood products- the adhesive in these products contains formaldehyde.

When cleaning ducts, what should be clean in order to be cleaned correctly?

Supply and return air ducts Registers, grills and diffusers Heat exchanger Heating and cooling coils Condensate drain pan, Fan motor and housing

If you are getting a lot of static electricity shocks, what should you suspect that is causing it?

The air is too dry.

How do electrostatic filters work?

These systems first remove larger particles in the prefilter. The remaining particles pass through a series of positive and negative charged plates. The particles are attracted to the negative plates. The remaining air passes through a charcoal filter.

What do molds produce that are unhealthy?

They produce volatile organic compounds (VOCs). These VOCs can irritate mucous membranes, produce headaches, cause inability to concentrate and dizziness.

What should be done with condensate pans on a regular basis?

They should be cleaned regularly and the drain lines kept free so the condensate can drain properly.

T or F: UV light is dangerous to look at, even if it invisible.

True- do not look at it when it is activated.

What type of UV light is considered germicidal?

UV-C light destroys microbes.

What medical conditions can CO cause?

headaches, tiredness, dizziness and nausea.