INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
PRESENTED BY:
Eng. Shehab S. Bekhet
INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
How much time - %, do we spend indoors??
2 INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY We Spend 90% of Our Time Indoors! !
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Shehab Bekhet Senior Mechanical Engineer Dar Al Handasah
More than 27 years of various experience, gained throughout long career path covers wide and diversified fields and ranges of responsibilities combining design, construction and technical back-up skills. The range of mechanical works cover preliminary & detailed design, preparation of specification and tender documents, follow up, approval of shop drawings and project management and construction supervision of building services including HVAC, plumbing, fire protection, building automation and control systems. Successfully contributed to design and construction of several large projects in more than 12 countries in the Gulf Area, Middle East, and Africa, such as: • Dubai International Airport- UAE • Higher College for Men & Women- UAE • Development of King Abdul Aziz Endowment for the Two Holy Mosques. • Al Hassa & Al Dammam Hospital – Saudi Arabia • Rafik Al Hariri Airport – Lebanon • Sheraton Hotel Rehabilitation – Egypt. A keynote speaker and administered many of training courses and seminars in various topics of HVAC systems. INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
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Introductory Film Indoor Ar Quality INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
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INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
The presentation covers the following main items:
Indoor Air Quality, (IAQ): . Definition. . Common Pollutants and health effect. . Sick Building Syndrome. . How to obtain Good Air Quality?
Ventilation: . Types of Ventilation. . Ventilation requirement for building occupants. . Ventilation Applications Notes: Public Toilets Ventilation. Commercial Kitchens Ventilation.
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Definition: (IAQ) represents the indoor air concentrations of pollutants that are known to affect people’s comfort, environmental satisfaction and health.
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11 INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY Indoor Pollutants groups
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Poor IAQ Health Impact
Serious health impacts resulting from poor IAQ include; lung cancer, airborne infection, SARS, and carbon monoxide (CO) poisoning.
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Building-related symptoms including; eye, nose and throat irritation, headache, fatigue, upper respiratory symptoms, and skin irritation and rashes.
This term has been used to describe the excess prevalence of this collection of symptoms, without attribution to specific illnesses.
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Q. How to obtain Good Air Quality? 1.Manage the design & construction stages of new buildings to achieve Good IAQ. 2.Limit contaminants from indoor and outdoor sources. 3.Exhaust contaminants from building equipment and activities. 4.Control moisture in building.
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INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
How to Manage the design stage to achieve Good IAQ? Consider the recommended fresh air & exhaust air requirement. Select HVAC systems to improve IAQ. Proper selection of building construction materials Building Pressure Control.
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Lack of IAQ consideration during Construction/Hand-over stage
Occupancy During Construction: .Large amounts of dust generated. .Gaseous contaminants from paint, etc... .Out gassing from new carpets, etc...
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Limit Contaminants From Outdoor Sources: Locate outdoor air intakes to minimize introduction of contaminants.
Limit contaminants from indoor sources: Dust (especially from paper). Lint, hair, fibers and Mold. Tobacco smoke. Volatile organic compounds from cleaning compounds, furniture, copiers, printers, etc. Toiletries and perfumes. 18 INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
Improper Building Operation & Maintenance Inadequate pest control. Improper operation & maintenance of HVAC system. Changing space usage: .Actual space usage is different from original design
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The importance of Indoor The Importance of Air Distribution Design Condition • To provide an acceptable thermal environment. • To provide well distributed fresh air. • To remove contaminated air.
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Important!
. There are many green building efforts that are impacting the provision of IAQ in buildings.
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Ventilation Ventilation air is the amount of outdoor air required to maintain Indoor Air Quality.
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Natural Ventilation Natural ventilation is Supplying and removing air without using mechanical systems.
BENEFITS OF NATURAL VENTILATION Energy savings. Occupant control.
There are some Cases in which natural ventilation may not be possible!
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Mechanical Ventilation
Mechanical ventilation systems circulate Ventilation air using ducts and fans.
• Better Indoor Air Quality • Better Control Avoid air leaking into the building from undesirable areas. Provide proper fresh air flow with selected locations for intake and exhaust.
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Pressure Relation Some Sorts of Cross Ventilation
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How to determine the required Ventilation rate? • Estimate no. of Occupants for each space/zone. • Determine the recommended fresh air for IAQ. (utilize ASHRAE application handbooks, and ASHRAE Standards 62.1 for indoor air quality). • Determine the recommended exhaust air rates for various areas/process, such as; toilets, kitchen, stores, etc…
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VENTILATION APPLICATION NOTES Why Proper Toilets Ventilation is an Important issue?
Surprising toilet facts!
• We spend about 3 years of our lives in the toilet! • An average person visits the toilet 2500 times a year! • Almost all buildings include toilets! • In order to avoid visiting poor ventilated public toilets, some people refrain from drinking liquids and suffer from dehydration!
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Common toilet exhaust and makeup system design A poor design of a toilet exhaust and makeup air system for a typical public men’s toilet is summarized as follows: The exhaust rate is based on 10 air changes / hour. Air is exhausted above each water closet and urinal. Makeup air is supplied by a constant volume reheat box connected to the A/C. unit.
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Using ACH per hour, to size ventilation system could be used as a guidance, where detailed layout is not available.
The ventilation rate is proportional to the source of odors which has no relationship to the volume of the room.
To determine ventilation rates; use the airflow per plumbing fixture (urinal or water closet) as prescribed by ASHRAE Standard 62.1.
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Number of Exhaust Grilles
Using less exhaust grilles results in almost the same airflow patterns.
Providing multiple exhaust grilles also leads to higher balancing costs.
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Toilets Makeup Air
Option 1: Door undercut or door louver
The undercut or door louver must be coordinated with the Architect.
Option 2: Ducted transfer from adjacent space(s) ceiling return air plenum.
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INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY KITCHEN VENTILATION Why do we care for kitchen ventilation?
More than 3 Billion CFM exhausted from Commercial Kitchens in the U.S!!
32 INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY kitchen ventilation system should: Types of Hoods Remove cooking fumes at the source. According to Configuration Remove excess hot air /introduce cool clean air.
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Exhaust flowrate according to Appliance Duty Classifications
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Proximity Hood
Is effective design
Effective Design Ineffective Design Island exhaust hood with air jet 35 INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
KITCHEN VENTILATION-HVAC INTEGRATION
Limited air transfer High air transfer
Restaurant Kitchen Restaurant Kitchen
INTRODUCTION TO VENTILATION & INDOOR AIR QUALITY
Demand-Controlled Ventilation (DCV) By Utilizing infra red sensors & duct temperature sensors to control the operation of the ventilation fans. operational stopped
Restaurant Kitchen Restaurant Kitchen
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