Power Ventilator For Industrial Building

Indoor Air Quality is an increasingly important issue in the work environment. The study of indoor air quality and pollutant levels within office environments is a complex problem. The complexity of studying and measuring the quality of office environments arises from various factors including:

- Building floor plans are frequently changing to accommodate increasingly more employees and reorganization.
- Office buildings frequently undergo building renovations such as installation of new carpet, modular office partitions and free-standing offices, and painting.

The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) has established a general guideline of 20 cubic feet of outside air per minute/per person for an office environment. This is a sufficient amount of air to dilute building contaminants and maintain a healthy environment. Indoor air quality complaints increase significantly in offices that are not supplied sufficient outside air.

Many of the apparent health symptoms are vague and common to both the office and home environment. Guidelines or standards for permissible personal exposure limits to pollutants within office buildings are very limited.

Many times odors are associated with chemical contaminants from inside or outside the office space, or from the building fabric. This is particularly noticeable following building renovation or installation of new carpeting. Out-gassing from such things as paints, adhesives, sealants, office furniture, carpeting, and vinyl wall coverings is the source of a variety of irritant compounds. In most cases, these chemical contaminants can be measured at levels above ambient (normal background) but far below any existing occupational evaluation criteria.

Various building studies indicate that the most likely sources of this problem are – poor ventilation, poor thermal conditions, too high or low humidity, emissions from office machines, copiers and other building contaminants and poor ergonomic layout of workstations.

Air enters office buildings or spaces through both mechanical ventilation systems as well as naturally through leaks around windows, doors, etc. Newer, larger buildings which are highly energy efficient due to sealed windows and heavy insulation primarily depend on mechanical ventilation. Older, small, and low occupancy office buildings can be adequately ventilated through natural sources which include air leakage through opened windows and doors, as well as through cracks in the windows and walls, and other openings.

In a modern office building, the heating ventilation and air conditioning system is designed to keep occupants comfortable and healthy by controlling the amount of outside air that is added to the building atmosphere, filtering both incoming and recirculated air to remove particulates and controlling the temperature. The HVAC system includes all heating, cooling, and ventilation equipment serving a building: furnaces or boilers, chillers, cooling towers, air handling units, exhaust fans, ductwork, filters, steam (or heating water) piping. A ventilation system consists of a blower to move the air, ductwork to deliver air to the room, and vents to distribute the air. A good ventilation design will distribute supply air uniformly to each area and especially areas with office machines. An effectively designed area will not have the supply and exhaust vent too close together because fresh air may be removed before it is adequately distributed throughout the area. Exhaust fans are often located a significant distance away from supply vents. A simple way to determine if the ventilation system is running a vent as a supply or an exhaust is by holding a tissue near the vent.] If the tissue moves, the air is being circulated and the direction the tissue is blown will determine the type of vent.

A ventilation system should provide for a comfortable environment with respect to humidity and temperature. The overall goal of climate control is to provide an environment that is not too cold, hot, dry or humid, and that is free from drafts and odors. Humidity refers to the amount of moisture in the air and extremes in humidification levels can influence how comfortable you may be. When the air is too humid, it makes people feel uncomfortable (wet, clammy) and can promote mold growth. On the other hand, low humidity conditions (which typically occur in the winter months) dry out the nasal and respiratory passages. Low humidity may be associated with an increased susceptibility to upper respiratory infections. Static electricity problems (affecting hair and clothes, particularly synthetic fibers) are good indicators of an office with low relative humidity.

Excessively high or low temperatures in an office area can also lead to symptoms in building occupants and reduce productivity. High temperatures have been associated with fatigue, lassitude, irritability, headache and decrease in performance, coordination and alertness. A number of factors interact to determine whether people are comfortable with the temperature of the indoor air. The activity level, age, and physiology of each person affect the thermal comfort requirements of that individual. Extreme heat, which is unlikely to be found in an office environment, can result in heat rash, exhaustion, and fainting. Workers who may be less alert or fatigued from a high temperature environment may be more prone to accidents.

An inadequately ventilated office environment or a poorly designed ventilation system can lead to the build up of a variety of indoor air pollutants. Air pollutants can originate within the building or be drawn in from outdoors. Examples of sources that originate outside a building include:

- pollen, dust and fungal spores
- general vehicle exhaust
- odors from dumpsters
- re-entrained exhaust from the building itself or from neighboring buildings

Examples of sources that originate from within the building include:

- building components and furnishings
- smoking
- maintenance or remodeling activities (painting, etc.)
- housekeeping activities
- unsanitary conditions (standing water from clogged drains or dry traps) and water damage
- emissions from office equipment or special use areas, like print shops, laboratories, or food preparation areas

The following recommendations and guidelines are useful in preventing indoor air quality problems:

* HVAC systems should receive periodic cleaning and filters should be changed on a regular basis on all ventilation systems.
* The ventilation system should introduce an adequate supply of fresh outside air into the office and capture and vent point air pollutant sources to the outside.
* Office machinery should be operated in well-ventilated areas. Most office machinery does not require local exhaust ventilation in areas that are already provided with 7-10 air changes per hour. Photocopiers should be placed away from workstations. Workers should vary work tasks to avoid using machines excessively.
* Office equipment should be cleaned/maintained according to the manufacturer’s recommendations. Properly maintained equipment will not generate unhealthy levels of pollutants.
* Special attention should be given to operations that may generate air contaminants (such as painting, pesticide spraying, and heavy cleaning). Provisions for adequate ventilation must be made during these operations or other procedures, such as performing work off-hours or removing employees from the immediate area, utilized.

Posted in Uncategorized | Comments Off

Commercial Building Ventilation And Cooling

Industrial Pressure Blower Co. suggests a few methods of effective building ventilation and cooling. In industrial plants where there is a high density of employees and many manual operations involved, an improvement in the environment can produce substantial benefits in terms of increased production, reduced errors, and a decline in complaints and absenteeism among employees. In other circumstances, the attentiveness of an audience or student group may be a factor that spells success or failure for the project.

To obtain a reasonable degree of personnel comfort in hot weather, there are three basic factors that should be provided for in the ventilation and coolong system of a commercial or industrial building.

REMOVAL OF EXCESSIVELY HOT AIR

The first step toward controlling the hot air porblem is to provide for the removal of excessively hot air from the building. This superheated air frequently mixes with the air in the cooler areas of the building to produce an overall temperature increase. As superheated air is frequently localized around heat-producing machinery, it should be exhausted from the building near its source.

SUPPLY COOLER AIR

As a rule, outside air temperatures are considerably cooler than those inside a building. As superheated air is exhausted, provision should be made to replace it with fresh, cooler, outside air. When high temperature air is replaced by outside air, a substantial improvement in the average ait temperature of the building results. Even where outside air temperature may be in the 80s or 90s, invariably it is 15 degress to 20 degrees cooler than the air it replaces. This is a very important improvement to the individuals affected.

VENTILATION

A very effective way to overcome the discomfort of a hot, stuffy room is to create a breeze. The circulation of air over a person’s body immediately causes a cooling effect on the skin. When air is passed over a moist surface, it will evaporate some of the moisture and thus lower the temperature of the surface. This is precisely what occurs when air circulates across the human body. By creating a gentle breeze throughout a room or area, a great deal of cooling comfort is provided for individuals who must work there. This pattern of air circulation is sometimes called “breeze conditioning”.

Commonly available prcatical methods of plants cooling are:

* Exhaust fans or Power Roof Ventilators (PRVs).

To do a satisfactory job of eliminating excessively hot air, it is usually essential to have powered wall and/or roof exhausters. These fans should also help to control air pressure within the building whether it be negative or positive pressure.

* Supply Fans or PRVs.

A large number of buildings use exhaust PRVs to exhaust fumes, smoke, dust or other contaminants unavoidable in the operation of the business. As a result, these buildings are frequently under a severe negative pressure. The solution to the problem of this kind is usually found in the use of supply fans or “make-up” air ventilators.

* Air Circulators.

If the exhaust and supply air requirements of a building have been carefully engineered and installed, and there continues to be a high instance of worker discomfort, the problem usually relates to the matter of air circulation. In this way, in addition to amximum benefit from the fresh, cooler air, occupants receive the added comfort of air circulation over their bodies and they are not adversely affected by the superheated air being exhausted from the building.

Posted in Uncategorized | Comments Off

Industrial Duty Exhaust Ventilator

Pollutants such as pesticides, harmful gases, smoke, pet dander, lead, asbestos, dust mites, paint fumes, grease etc get released into indoor air due to daily activities such as cooking, smoking, burning fuel, bathing, renovating etc. In addition to these pollutants, activities such as bathing, cooking, and washing also release excess moisture in the air and make indoor air extremely humid. If not ventilated adequately, these added pollutants and increased moisture levels can decrease the quality of indoor air greatly, thereby leading to various problems such as:

Health problems including asthma, allergies, nose bleeds, skin rashes, headaches, nausea, and other breathing disorders. In fact, according to the Environmental Protection Agency, a large percentage of the over 20 million annual asthma cases in the US alone can be attributed to bad indoor air quality.

- Split, warped and rotted furniture due to excess humidity.
- Cracked and peeling paint on the walls.
- Formation of fungus, mold spores, and mildew, which in turn lead to severe health problems.

Exhaust fans are very effective at any building ventilation. Without proper ventilation, the air inside your home can get filled with harmful contaminants and disease causing pathogens.

An exhaust fan is a mechanical ventilation device that helps to draw out stale and impure air from your home and bring in fresh air, thereby improving the quality of indoor air. Exhaust fans are typically ducted to the exteriors of your house, through which bad indoor air can effectively be removed from your living space.

Exhaust fans are classified into various types, mainly depending on the type of mount and the location where you need to install the fans. The different types are:

1. Ceiling Mounted Exhaust Fans: As the name suggests, ceiling exhaust fans are those which are installed in the ceiling. Such fans expel stale air from your home upwards through the roof. The fan is connected to ducting, which is exhausted outside the home via an external vent, like a roof cap or soffit exhaust vent.

2. Inline Exhaust Fans: Unlike ceiling exhaust fans that are installed directly into the ceiling, inline exhaust fans are typically mounted in-between ducting, hence the name inline fan. For instance, if you wanted to ventilate an area that did not have clearance or space for a ceiling mount fan, you would make use of inline exhaust fans to ventilate such areas. The exhaust fan would be placed in between the ductwork and the stale air would travel through the ducts and ultimately be expelled from your home. Since inline fans are not mounted directly to the ceiling, they are very quiet. When installing an inline fan, to reduce noise, we recommend using an insulated flex duct that is at least eight feet long from the intake port on the ceiling to the inline fan.
Inline exhaust fans are ideal for exhausting areas or rooms where you cannot, or do not wish to install the exhaust fan directly. Since these types of exhaust fans are mounted in remote areas, they are also referred to as remote mounted exhaust fans. Inline exhaust fans can either be single-port (exhausting from a single area) or multi-port (exhausting from multiple areas).

3. Wall Mounted Exhaust Fans: These exhaust fans are installed on walls. Since they are installed on exterior walls of the home and not on interior walls, the stale air has a direct route to the outside of your home and thus no duct work is required in installing these exhaust fans.

4. Combination Exhaust Fans: Exhaust fans are also available as combination units. You have the choice of a fan-light combination where the exhaust fan provides illumination as well, or heat-fan-light combination wherein you get a heater, light and ventilating fan all in a single device.

5. Exterior Remote Mounted Exhaust Fans: While most other exhaust fans are installed inside your home and push stale air out, exterior remote mounted fans are installed outside your home and pull out stale indoor air instead of pushing it out. The main benefit of these exhaust fans is that regardless of however noisy they are, most of the noise remains outside your home.

6. Kitchen Range Exhaust Fans: These fans are mounted inside the range hood over your kitchen stove. Such fans not only help to rid your kitchen of stale air but also help to expel bad odors and reduce moisture levels in your cooking area.

These several types of exhaust fans can be used for complete ventilation of your bilding including intermittent local ventilation for baths, kitchens, dryer rooms; continuous whole building ventilation, and for exhausting hard-to-air spaces such as crawl spaces, attics, and basements.

Thus, by using exhaust fans to ventilate your building efficiently and completely, thereby improving indoor air quality, you can avoid of all these problems.

When sizing an exhaust fan that does not open directly to the outside but is ducted, it is important to ensure that the exhaust fan has the capability to move stale air throughout the duct and ultimately to the outside. Here, we first need to understand what static pressure and equivalent duct length is.

Inside every duct, there is a constant pressure being exerted at any point from all directions. When an exhaust fan moves air through the duct, the air counters resistance from this pressure which is known as static pressure. Thus, an exhaust fan has to have the ability to overcome the static pressure in a duct so as to effectively duct stale air to the outside of your home. This can be done by calculating the equivalent duct length of any duct.

Posted in Uncategorized | Comments Off