Ruks Engineering Ltd. IAQ Systems

Introduction | Feasibility Study | Ozone Levels, Permissable Safe Limits, Methods of Control
Selection of Generators | Specifications | Drawings | Reference | Schematic Drawings
Ozone Generators | C02 Monitors | Ozone Monitors | VOC Monitors

IAQ WITH CONTROLLED AND REGULATED OZONIZATION

INTRODUCTION
Modern commercial buildings are infested with wide range of pollutants of chemical and organic origin, called Volatile Organic Compound (VOC). Origin of these is from many sources;

Interior furnishings: Use of synthetically produced interior furnishing is high in most modern buildings. Examples of these are: Carpets, curtains, protective coatings such as veneer, polish, stain proofing, ceiling tiles, paint, adhesive used to glue carpets, cleaning agents etc. They emit continuously toxic gases over the course of their life, some of which are carcinogenic.
Cigarette smoke: This is a common occurrence in many public buildings, though the present trend is to make all buildings smoke free. Cigarette smoke emits many chemicals, many of these are proven to be carcinogenic, emits odor and creates heavy smoke.
Internally generated pollutants: From occupants, office machines, janitorial and maintenance products.
Many toxic gases constitute above VOC, such as formaldehyde, toluene, benzene, xylene, naphtha etc. Due to prolonged use of indoor space, exposure of occupants to these pollutants is high. This causes variety of disorders ranging from simple irritation to asthma, fatigue, reduced immune systems, to carcinogenic disorders.

Outdoor air: Outdoor air in many large cities are highly polluted with automotive exhaust and industrial pollutants. These are introduced indoor through fresh air intake. CO2 level may also be high in outdoor air.

Other forms of indoor pollutants in modern buildings are from microbes and fungi. Conditions prevailing in cooling coil and HVAC duct offer ideal grounds for their breeding and propagating. Through air vents, they enter indoor premises. Damp indoor conditions is another source of their breeding.

ROLE OF OUTDOOR AIR IN HVAC SYSTEMS
Traditionally, outdoor air is used in HVAC systems to achieve following functions;

To dilute VOC and organic pollutants. Fairly large part of outdoor air is consumed to perform this function.
To restrict build up of CO2 to within permissible level. OSHA specified level is 1000 to 3000 PPM depending on the activity performed indoor.

Treated outdoor air is expensive to use, as it adds significantly to both capital and operating costs of the HVAC system.

INTRODUCTION TO OZONE
Ozone is a colorless gas, which in low concentrations (0.02 PPM and below) is odorless. In higher concentrations, it has a characteristic pungent odor. It was discovered in 1785 accidentally by a German scientist, and named after the Greek word 'ozein', meaning 'to smell'. It is seldom produced in nature, except during lightning. It is represented by the chemical formula 'O3'. Its molecular weight is 48. It is 1.6 times heavier than air, with specific weight of 8.9 Cft per Lb. It is 3 atom molecule of oxygen. Oxygen we breathe is a 2 atom molecule.

EFFECTS OF OZONE ON VOC AND HYDROCARBONS
Ozone has 3 very unique and important properties which make it ideally suited for removal of chemical pollutants, odors, and smoke in indoor air. First, it is the most powerful oxidizing agent commercially available. It is 52% more powerful than gaseous chlorine in terms of its oxidizing potential. Second functional advantage of ozone is it is a very unstable gas. Its half life at room temperature of 75° F is no more than 10 minutes. If not consumed by pollutants in the air for oxidation, ozone quickly reverts back to its more stable molecular form of di atomic oxygen, O2. Hence, if the system is well designed, it is nearly not possible to build up a high level of ozone. Ozone cannot be stored in any form, or in any container. It should be produced locally at site, and consumed immediately. The third advantage of ozone is it has a low grade smell at concentration of about 0.02 PPM. This eliminates the need to use any sophisticated monitors to ensure level of ozone in indoor environments is well within acceptable limits. Due to these properties, ozone is used to remove various types of chemical pollutants in air.

Organic pollutants are readily oxidized by ozone. The final products of oxidation are mostly environmentally friendly and far less harmful to humans than the original compounds. Theoretically, if sufficient ozone is made available, almost all compounds will achieve total and complete oxidation to the basic fundamental compounds such as carbon dioxide, moisture and oxygen. To achieve this state, the original compounds go through many intermediate stages. In reality, total oxidation may not always occur, due to many reasons. However, most products are oxidized to compounds that are usually less harmful. For example carbon monoxide (CO), a very harmful compound is oxidized to CO + O3 + CO2 + O2, and formaldehyde, a carcinogenic compound is oxidized as 2(CHOH) + 2O3 + 2H2O + 2CO2 + O2.

OZONE AND MICROBES CONTROL
Ozone helps in removal of fungi such as mold, mildew, spores, dust mites etc. These are responsible for allergies typical of indoor and air conditioned environments, such as sneezing, cold, itchy eyes, and problems of upper respiratory disorders. Some argue microbes are not present in well kept upscale buildings. This is a misconception, because microbes are propagated in HVAC ducts. Through air grilles, they enter indoor environment and cause allergy related problems.

Ozone is excellent for removal of fungi without using any chemicals. Ozone interferes with the micro biology and growth propagation of the microbes and gradually eliminates them.

It is important to note that while ozone removes chemicals quite readily in a short time, its ability to remove fungi is spread over several weeks. This is because ozone depletes their colonies and reduce them to levels harmless to humans.

COMPARISON WITH AIR STREAM FILTERS
Air stream filters capture pollutants from air, if passed over them. Performance of this depends on the frequency of passage of air over it, which typically in HVAC systems is about 15 minutes (assuming total air change of 4 per hour). This also implies the pollutant is present in the space for period of 15 minutes, before it is captured by the filter. This is fairly long period of time for pollutant to cause sufficient harm. In ozonized system, ozone is present in low concentration in the space at all times. This reacts with pollutant in a very brief period of time, and thus prevent its build up.

OBJECTIVE WITH RUKS OZONE SYSTEMS IS TO ACHIEVE FOLLOWING

To provide satisfactory indoor air environment in the premises using the INDOOR AIR QUALITY PROCEDURE RECOMMENDED BY ASHRAE STANDARD 62-1999 which provides a direct solution by restricting the concentration of known contaminants of concern to some specified acceptable levels.
To restrict CO2 level in indoor environment to OSHA, ACGIH, WHO specified standards, and/or to recommendations of ASHRAE STANDARDS 62-1999.
To rationally reduce outdoor air intake into the HVAC system, resulting in substantial reduction in capital and operating costs of HVAC system.
To provide indoor and AHU system free of fungi and microbes.
To reduce the need to clean air ducts and AHU casings, in the premises.
To ensure concentration of VOC and toxic gasses is very low in the premises.
Where possible to ensure CO2 build up does not exceed 700 PPM indoor to outdoor differential (ASHRAE 62-1999), or maximum of 1000 ppm.
Aim to achieve high overall indoor air quality, low CO2 level, and yet achieve this with reduced outdoor air intake.

FEASIBILITY STUDY

Detailed Feasibility Study and Return and Investment Analysis can be custom provided to suit clients specific requirements, several site specific information is needed to provide the study.

For your specific needs, please contact:

Ruks Engineering Ltd
18 Automatic Rd, Unit 18
Brampton, Ontario
L6S 5N5
Canada

Tel: (905) 789 9652 Fax: (905) 789 0381
email: info@rukseng.com

Or Contact Our Distributors

Introduction | Feasibility Study | Ozone Levels, Permissable Safe Limits, Methods of Control
Selection of Generators | Specifications | Drawings | Reference | Schematic Drawings
Ozone Generators | C02 Monitors | Ozone Monitors | VOC Monitors