E-NEWS PAKISTAN HVACR SOCIETY NOVEMBER -MARCH 2020 www.hvacr.org.pk HEAD OFFICE INNAUGURAL CEREMONY The HVACR society of Pakistan inaugurated its headquarters in the city of Islamabad. The simple yet impressive inauguration ceremony, organized in the newly developed headquarters located in the F-8 sector of Islamabad was widely attended by members from all across the country including Karachi, Lahore and Faisalabad.Theinauguration ceremony started with the ceremonial ribbon cutting ceremony. Engr Khurram R. Malik President, Pakistan HVACR society and Mr. Ahmad Naeem Chughtai, Hon.General Secretary, along with the previous presidents, cut the ribbon to officially mark the opening of the society headquarters. All attendees prayed for the success and growth of HVACR society. UPDATE The first meeting chaired by President Khurram Malik was held at the HVACR society headquarters. A soft launching of the HVACR society mobile application was also held at the event. New Staff members were introduced to all EC Members.Decisions regarding training centres and student scholarship campaign were made. HVACR Society Lahore Chapter, under the leadership of it`s chapter chairman Mr. Muhammad Aamer inaugurated “Skill Development Center” at Lahore. The idea behind this opening is to train the labor in HVACR sector and to create employment. The Skill Development committee was headed by Mr. Sajjad Haider, who, with the help of his team worked day and night to bring this idea into reality in the shortest possible time. The Center was inaugurated by Mr. Khurram R. Malick, President PHVACR Society with Mr. Ahmad Naeem Chughtai, Hon. General Secretary and a big number of team members. Pakistan HVACR EXPO 2020 is postponed due to panademic disease till 22, 23 & 24 July 2020. Keeping in view current situation all other activities of society has also been postponed till lockdown. INNAUGURATION OF PAKISTAN HVACR FIRST SKILL DEVELOPMENT CENTRE EC MEETING
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E-NEWSPAKISTAN HVACR SOCIETY
NOVEMBER -MARCH 2020
www.hvacr.org.pk
HEAD OFFICE INNAUGURAL CEREMONY
The HVACR society of Pakistan inaugurated its headquarters in the city of Islamabad. The simple yet impressive inauguration ceremony, organized in the newly developed headquarters located in the F-8 sector of Islamabad was widely attended by members from all across the country including Karachi, Lahore and Faisalabad.Theinauguration ceremony started with the ceremonial ribbon cutting ceremony. Engr Khurram R. Malik President, Pakistan HVACR society and Mr. Ahmad Naeem Chughtai, Hon.General Secretary, along with the previous presidents, cut the ribbon to officially mark the opening of the society headquarters. All attendees prayed for the success and growth of HVACR society.
UPDATE
The first meeting chaired by President Khurram Malik was held at the HVACR society headquarters. A soft launching of the HVACR society mobile application was also held at the event. New Staff members were introduced to all EC Members.Decisions regarding training centres and student scholarship campaign were made.
HVACR Society Lahore Chapter, under the
leadership of it`s chapter chairman Mr.
Muhammad Aamer inaugurated “Skill
Development Center” at Lahore. The idea behind
this opening is to train the labor in HVACR sector
and to create employment. The Skill Development
committee was headed by Mr. Sajjad Haider, who,
with the help of his team worked day and night to
bring this idea into reality in the shortest possible
time. The Center was inaugurated by Mr. Khurram
R. Malick, President PHVACR Society with Mr.
Ahmad Naeem Chughtai, Hon. General Secretary
and a big number of team members.
Pakistan HVACR EXPO 2020 is postponed due to panademic disease till 22, 23 & 24 July 2020. Keeping in view current situation all other activities of society has also been postponed till lockdown.
INNAUGURATION OF PAKISTAN HVACR
FIRST SKILL DEVELOPMENT CENTRE
EC MEETING
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E-NEWS Nov-march 2020
By the Grace of Allah Almighty on 18 Nov, 2019 Paki-
stan HVACR society announced its first Pakistan HVACR student chapter at Government College of
Technology, Rawalpindi. Pakistan HVACR also donated
Rs:150,000/ scholarships for deserving students of
GCT.Pakistan HVACR Society and the Society President
appreciated the dedicated effort of Mr. Rauf Chaud-
hary President district Board of Management TEVTA
Govt. Of Punjab.Mr. Ather Siddiqi also donated tree to
college. Mr. Riaz Baig is being assigned as the Student
advisor and mentor of GCT, Rawalpindi for the HVACR
Students on behalf of Pakistan HVACR Society.
By the Grace of Allah Almighty
Pakistan HVACR Society has
hired new staff i.e Maham Ayub as Marketing Executive Abeer
ChohanasGraphicKa lsoom
Rashid as Receptionist and Mr.
Zia Shoukat as Chief
Accountant
FINANCIAL ASSISSTANCE
COVID-19
In this hour of need Pakistan HVACR Society has provided financial assisstance to members of society in need . Society has assissted 21 members 1 in islamabad and
President and will be put up ffor final approval of Executive Council in its next meeting. The SOP will be implemented across all offices ofthe Society once approved.
NEW HIRING ACOUNTING SOP MOBILE APP
Pakistan HVACR Society will be
launching it`s first mobile app with all features to assisst members.
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E-NEWS Nov-march 2020
6 MONTHS REPORT
NOV 2019 TO APRIL 2020SOCIETY PERFORMANCE
THIS EXECUTIVE COUNCIL HAS TO ITS CREDIT MANY ACHIEVEMENTS SOME OF THE SALIENT ACHIEVEMENTS
ACTIVITIES ISLAMABAD
CHAPTER
LAHORE
CHAPTER
KARACHI
CHAPTER
TOTAL
TECHNICAL SEMINARS & CPD 06 09 04 19
STUDENT BRANCHES 04 0 02 06
CRICKET LEAGUE 01 01 00 03
DONATIONS / SCHOLARSHIPS 01 0 0 01
GET TOGETHERS 02 01 0 02
LOCAL COUNCIL MEETINGS 07 04 10 21
ORG. COMMITTEE MEETINGS 08 0 08
OTHER ACTIVITY 01 02 03
NEW MEMBERSHIPS 08 36 48 92
MEMBERSHIP STATUS
3 DAY WORKSHOP
STAFF APPOINTMENT
APP LAUNCH
MOU
SOCIETY CHAPTERS ACTIVITY
Successfully Conducted three days Technical Workshop in Islamabad & Karachi
Appointed More Staff in HQ office
Launching of Society App
President’s Meeting with OZONE Cell management and signed MOU
It is really appreciable that Society Membership Database is expanding rapidly and at the moment there are 2377 members on the Society roster. When this Council took over, there were in all 2299 members therefore, we have got addition of 078 members. Significant increase in Membership in 6 MONTHS, especially due to the equal efforts of Society Chapters.
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E-NEWS Nov-march 2020
3 Day MIA Technical Training workshop - 13-15 January 2020
Seminar on Emotional Intelligence - On Jan 29, 2020
Seminar on Air Serve - On Feb 22, 2020
Overview of DDC Controls for HVACR - 11 March 2020
ISLAMABAD CHAPTER LAHORE CHAPTER
Jointly planning meeting of President PHVACR Society & ASHRAE CPC Conference Team regarding upcoming 27th Conference 2020 - January 17, 2020
Practical Training Session on Difference between Inverter & Non-Inverter Technology for Students of VTI – Tehsil Laliyan Chiniot - January 18, 2020
Presentation on Water & Heat Potential of Air Conditioning System - January 21, 2020
Presentation on VRF and its Implementation Challenges - January 23, 2020
Presentation on "VFD vs Inverter Technology - January 24, 2020
A Half- Day Training Session on Topic “Fundamentals of HVACR” - January 28, 2020
International Conference on Mechanical Engineering (ICME-20) - January 29-30, 2020
Practical Training Session on Difference between Inverter & Non-Inverter Technology for Students of VTI Safdarabad, District Sheikhupura. - February 02, 2020
KARACHI CHAPTER
Chartering 1st Student Branch of Pakistan HVACR Society - January 20, 2020
Technical Seminar on VFD vs Inverter Technology & Fundamentals of HVACR - Feb 1, 2020
Technical Seminar on Fundamental Instrumentation & Control For HVAC System - Feb 8, 2020
3 Day Course for Technical Students on Basic of Air Conditioning at Karachi - Feb 11, 12 & 13, 2020
President PHVACRS along with Student Activities Committee jointly arranged a meeting to discuss new PHVACR student branch & also announced that the first technical 3 day course for technical students on Basic of Air Conditioning - On 7 January 2020
SEMINARS1st One day Technical Skills Development workshop on DC inverter AC for RAC students of Vocational Training Institute - Faisalabad - December 05, 2019
Presentation on Understanding Total Quality Management -December 17, 2019
Pakistan HVACR Society shake hands with legends of Pakistan Younas Khan , Jahangir Khan & Aijaz aslam for the noble cause of Student Scholarship Program.
Pakistan HVACR Society has joined hands with Legendary Cricketer YOUNUS KHAN, Iconic Squash
Player JAHANGIR KHAN and famous AIJAZ ASLAM in noble cause of STUDENT SCHOLARSHIP
PROGRAM. All the three personalities are legends in their own right and need no introduction globally.
They have very graciouslly consented to help the society to run its campaign to generate funds for
providing scholarships to deserving students.
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E-NEWS Nov-march 2020
Pakistan HVACR Society has realized the need of guideline on COVID-19 HVAC DESIGN AND INDOOR
AIR QUALITY.Society has worked really hard to publish the basic understanding of COVID-19 and HVAC
concerns
HOUR OF NEED
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HVAC SYSTEMS & INDOOR AIR QUALITY
COVID 19 –PANDEMIC
BY MR.MOHAMMAD RIAZ BAIG P.E
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E-NEWS Nov-march 2020
HVAC SYSTEM & INDOOR AIR QUALITY
MR.MOHAMMAD RIAZ BAIG
COVID 19 –PANDEMIC
Currently ASHRAE is only referring existing standards and guidelines and have announced a Society-wide effort to respond to the current global COVID-19 pandemic. To provide guidance on how to ensure that buildings are prepared for future epidemics, ASHRAE has formulated a task force headed by Presidential Member DR William Bahnfleth. ASHRAE Website will be updated as and when new information is available. Please visithttps://www.ashrae.org/technicalresources/resources for additional information.
ARTICLE
Mr Baig retired as lead Project Engineer from Saudi Aramco, Saudi Arabia where he worked for over 33 years. Prior to that he served Pakistan ordinance factories for 8 yrs. He is an ASHRAE member since 1997, past ASHRAE NPC president and current member BOG. While carrying over 50 years in the respective field, he has been involved in almost every field of HVAC i.e. Design, construction, Controls, Inspection, commissioning, Testing/balancing & Operation and Maintenance. In addition to HVAC, he has also executed multimillion dollar and multidiscipline projects. During his stint with Saudi Aramco, he got numerous professional developmental trainings/specialty courses from USA, Europe and Middle East. He was also a member of ARAMCO’s HVAC standards review committee. While partly retired, takes keen interest in knowledge sharing.
In times like these, when emotions run high and everyone is concerned, there is a growing concern among the HVACR professionals regarding COVID 19 isolation centers, quarantine facilities and their HVAC systems. To address this, we have compiled this interim document with reference to available resources as of now and the document may be complemented with new evidence and information when it becomes available. The purpose of this guidelines is NOT as how to design health care facilities in details. We also understand that pres-ently there is a desperate need of new quarantine and isolation centers in new or converted buildings. Due to this it may be difficult to comply with the respective standards due to urgency and numer-ous reasons. However, PHVACR/ASHRAE local chapter members will refer to respective standards and guidelines. In case of any deviation, respective designer/consultant is to be consulted. This docu-ment is merely a guidance document and shall not be liable for any legal action.
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E-NEWS Nov-march 2020
WHO declared COVID-19 as Pandemic causing respiratory illness (like the flu) with symptoms such as a cough, fever, difficulty breathing, body ache etc. As per current scope & definition of modes of transmission by WHO released guidelines, SARS-Coronavirus Size 88nm to 160nm (0.088 micron to 0.160 micron) transmission is considered through Opportunistic Airborne & droplet mode Only. However, residual contaminants can travel through air currents caused by central air conditioning system ducts, where all or some air in the building is circulated and can contribute to the spread of the disease. COVID19 is fairly new and should be seriously considered with all the precautionary measures. The HVAC systems should be looked at as airborne infectious disease. Corona patients based on their nature of illness must be kept isolated in isolation centers and should not be mixed up with other areas of a hospital. That is why China has built dedicated centers for this. Now, if a hospital with Corona patients having mixed HVAC system, means there is a possibility of cross contamination and its spread. If an existing Hospital with Central AC system is used as Corona centers, its AC system needs to be looked at.
In hospitals, the risk of airborne virus diffusion mainly depends on airflow behavior and changes in direction caused by supply air and exhaust air locations. An improved isolation room ventilation strategy is found to be the most efficient in removing contaminants based on observations and simulation results. There are different classifications of rooms in hospital ie Class S, N & P: (Ref: International Health facilities guidelines) while ASHRAE looks at it according to its utilization. It is up to the health care professionals to decide (according to WHO recommendations) which patient is critical or otherwise and accordingly serious COVID patients should be kept in class N Isolation rooms. Class N –Negative Pressure isolation rooms are used for patients requiring airborne nuclei isolation. Negative room air pressure, where others are protected from any airborne transmission from a patient who may be at an infection risk.
CLASSIFICATION OF ISOLATION ROOMS
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a. PRESSURE RELATIONSHIP: A negative pressure isolation room is used for patients with airborne infections. According to CDC, a patient known to have contracted the coronavirus can spread it person-to-person. Negative-pressure isolation room therefore is designed to help prevent the spread of a disease from an infected patient to others in the hospital.
b. AIR CHANGES (SUPPLY / EXHAUST AIR). Negative-pressure isolation rooms require a minimum of 12 air changes per hour with min 2ACH fresh air and must maintain a minimum 0.1inch Water gauges (25Pascals) negative-pressure differential to the adjacent corridor whether an anteroom is utilized. When an anteroom is provided, airflow should be from the corridor into the anteroom, and from the anteroom into the patient isolation room.
c. AIR FILTRATION: The air-handling unit serving the isolation rooms requires minimum-efficiency reporting value
(MERV) 7 pre-filters, with either MERV 14 or high-efficiency particulate air (HEPA) final filters.
d.TEMPERATURE: An ambient temperature of 72F to 75F should be maintained.
e.HUMUDITY: Dry air causes particles to stay airborne for longer, and this increases the chance of viral infections while excessively humid air stimulates the growth of bacteria, mold and dust mites. These organisms have a negative impact on indoor air quality and occupant health. Therefore, a humidity level of 40% to 60% should be maintained.
f. AIR MOVEMENT: When designing the mechanical systems to support isolation rooms, the designer must consider not only the airflow required to maintain the proper pressure differential, but also flow pattens/direction, location of the equipment, the serviceability of the equipment and equipment redundancy. Depending on the number and type of
isolation rooms in the facility, it is generally more economical to provide a single larger system to serve multiple rooms than multiple smaller systems.
g. EXHAUST: Exhaust Air should be directed to outside high above the roof level at least 10’, with speed greater than 2500 fpm, considering minimum separation distance requirements from air intakes, stacks, operable windows etc. Exhaust is required to pass through HEPA Filters / UV Treatment depending on risk assessment. Recirculation of Air is discouraged from Isolation Rooms.
AIIR rooms are a specialized application of a hospital's HVAC system for Messel, COVID -19, where the airflow supplied into the room is balanced with exhaust airflow to create at least 0.1” Water of gauges (25 Pascals) negative differential pressure with respect to an adjacent space, usually the hallway or an anteroom. Air-conditioning systems for negative pressure Isolation Rooms should be connected to an emergency power supply to maintain air pressurization in the event of a power failure. The room requires labelling as a negative pressure Isolation Room.
AIRBORNE INFECTIOUS ISOLATION ROOMS (AIIR)
THINGS TO CONSIDER IN AN
HVAC SYSTEM FOR ISOLATION ROOMS
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With growing needs, this seems to be a major concern and each building is to be looked at depending on its nature. If there is no HVAC system installed, then new systems must meet the minimum requirements depending on the nature of the building. Respective design consultants must look at not only the cooling requirements but also indoor air quality. Portable air cleaning systems are also recommended. At present, only WHO has recommended as to how the new isolation centers to be made. Please see the link below for further details
b. Functional Check of Dampers, Control Valves, Instrumentation.
c. Inspection of Equipment/Ducting for Accumulation/Growth of Undesired Dust / Microorganisms
d. Inspection & Cleaning of Coils / Pre or Intermediate Filters / Ducting
e. HEPA filters to be tested on site when they are first installed and every six months thereafter to confirm that they are operating at their design efficiency.
In order to have reliable and efficient operation of the system, it should be adequately maintained as per following but only limited to. a. Monitoring & Verification of Design Performance Parameters of System like Air Change Rate, Pressure Differential, Temperature & Humidity
CONVERTED HOSPITAL AREAS FOR COVID PATIENTS
EXISTING HOSPITALS ISOLATION ROOMS We understand that the existing isolation rooms of a hospital has
already been designed to cater for the needs, if not it should be looked at as per the health care facilities guidelines.
Since these areas were previously used for different purposes, consultants must look into and see the changes required to house COVID patients of different stages of disease.
8. Guidelines for the Classification & design of Positive / Negative Pressure Rooms 9. MERV Table – ASHRAE 10. ANSI / ASHRAE Standards 62.1 – 2019
DISCLAIMERThis article is a preliminary finding and guideline all comments and suggestion are welcome to fine tune. Pakistan HVACR Society and
the author may be indemnified on any implementation. It is suggested to further investigate before any final execution.
REFRENCES & ADDITIONAL RESOURCES:
Note: Document compiled by Mohammad Riaz Baig with assistance
from Mr Asif Iqbal & Zeeshan Siddiqui
COVID-19 PANDEMIC
HVAC SYSTEMS & INDOOR AIR QUALITY
TECHNICAL ARTICLE
Mr. Zeeshan is a professional Mechanical Engineer graduated from NED University. He has worked in many position from Project Engineers to Sales Engineers. Mr. Ahmed is associated with Carrier for last 11 years and has spend most of the 18 years in Dubai managing the Pakistani market. He has vast know how of major air conditioning equipment and has presented many technical papers.
Recently he has volunteered his time to assist Pakistan HVACR Society and its member in writing a basic understanding of Covid 19 and HVAC design. His study is preliminary about Covid 19, type of isolation rooms related to HVAC Design and System.
We as a Society is very much obliged with Mr. Zeeshan Ahmed P.E who has taken his timeout to give something in brief writeup to help society members to understand the basic Air Conditioning design.
Should anyone have any suggestion, feedback please feel free to give so we can issue an addendum.
PHVACR Society
ABOUT THE AUTHOR
Coronavirus disease (COVID-19) is
an infectious disease caused by a
newvirus.The COVID-19 virus
spreads primarily through droplets
of saliva or discharge from the nose
when an infected person coughs or
sneezes.The COVID-19 virus is
approximately 0.125 Micron or 125 nanometers in diameter. (Source:
National Library of Medicine)
However, it often travels in biological
aerosols from coughing and
sneezing which range in size from
0.5 – 3.0 Micron.
INTRODUCTION1.Restrict Air movement.2.Dilute concentration.3.Temperature.4.Humidity.5.Minimize risk of Transmission of airborne
SAFTEY & PREVENTION TIP
1.STAY home as much as you can2.KEEP a safe distance3.WASH hands often4.COVER your cough5.SICK? Call ahead
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E-NEWS Nov-march 2020
The main ways of virus transformation are as follows:
1.Direct Contact Less than 1 meter.
2.Droplets – when the droplet particles are < 5μm in diameter, they are referred to as droplet nuclei according to World Health Organization (WHO).
i)Mouth
ii)Nasal
iii)Eyes
iv)Through air at short
distance – talk.
v)Indirect – Surfaces such as
metal or floor etc.
3.Airborne Transmissioni)Airborne droplet Nuclei (Small droplet). These droplets rapidly evaporate in the air leaving.ii)Dust particles in the environment.
MODES OF INFECTION TRANSIMISSION OF VIRUS
NOTEWhen the droplet particles are >5 -10 μm in diameter they are referred to as respiratory droplets according to World Health
Organization (WHO).
A Suspension of fine solid or liquid particles in gas smoke, fog, and mist are named Aerosols.
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virus is primarily transmitted between people through respiratory droplets and contact routes.In an analysis of 75,465 COVID-19 cases in China, airborne transmission was not reported – WHO Website.Droplet transmission occurs when a person is in in close contact (within 1 m) with someone who has respiratory symptoms(e.g., coughing or sneezing) and is therefore at risk of having his/her mucosae (mouth and nose) or conjunctiva (eyes) exposedto potentially infective respiratory droplets.
Therefore, transmission of the COVID-19 virus can occur by direct contact with infected people and indirect contact withsurfaces in the immediate environment or with objects used on the infected person (e.g., stethoscope or thermometer).In the context of COVID-19, airborne transmission may be possible in specific circumstances and settings in which proceduresor support treatments that generate aerosols are performed; i.e. open suctioning, administration of nebulized treatment,disconnecting the patient from the ventilator etc..
MODES OF INFECTION TRANSIMISSION OF VIRUS
COVID-19
CONCLUSION
NOTE
Based on the available evidence, including the recent publications mentioned above, WHO continues to recommenddroplet and contact precautions for those people caring for COVID-19 patients. WHO continues to recommend airborne precautions for circumstances and settings in which aerosol generating procedures and support treatmentare performed, according to risk assessment.
WHO is aware of other studies which have evaluated the presence of
COVID-19 RNA in air samples, butwhich are not yet published in
peer-reviewed journals.
www.hvacr.org.pk
E-NEWS Nov-march 2020
Protective Environment named as – PE rooms are hospital rooms designed to protect a high-risk immunocompromised patient from human and environmental airborne pathogens. These are positive pressure rooms intended to keep patients safe during recovery from cancertreatment or stem-cell transplant.
CLASSIFICATION OF ISOLATION ROOMS
I n h o s p i t a l s , t h e r i s k o f a i r b o r n e v i r u s d i f f u s i o n m a i n l y d e p e n d s o n a i r f l o w b e h a v i o r a n d c h a n g e s i n d i r e c t i o n c a u s e d b y s u p p l y a i r a n d e x h a u s t a i r l o c a t i o n s . A n i m p r o v e d i s o l a t i o n r o o m v e n t i l a t i o n s t r a t e g y h a s b e e n d e v e l o p e d a n d i s f o u n d t o b e t h e m o s t e f f i c i e n t i n r e m o v i n g c o n t a m i n a n t s b a s e d o n o b s e r v a t i o n s a n d s i m u l a t i o n r e s u l t s . T h e r e a r e d i f f e r e n t c l a s s i f i c a t i o n o f r o o m s i n h o s p i t a l :a ) C l a s s S – S t a n d a r d P r e s s u r e R o o m . A S t a n d a r d r o o m w i t h n o r m a l a i r - c o n d i t i o n i n g i s a p p r o p r i a t e .b ) C l a s s P – P o s i t i v e r o o m a i r p r e s s u r e w h e r e a n i m m u n e - c o m p r o m i s e d p a t i e n t i s p r o t e c t e d f r o m a i r b o r n e t r a n s m i s s i o n o f a n y i n f e c t i o n .c ) C l a s s N – N e g a t i v e P r e s s u r e R o o m . T h e s e r o o m s a r e u s e d f o r p a t i e n t s r e q u i r i n g a i r b o r n e n u c l e i i s o l a t i o n . N e g a t i v e r o o m a i r p r e s s u r e , w h e r e o t h e r s a r e p r o t e c t e d f r o m a n y a i r b o r n e t r a n s m i s s i o n f r o m a p a t i e n t w h o m a y b e a n i n f e c t i o n r i s k .d ) C l a s s Q – N e g a t i v e r o o m a i r p r e s s u r e w i t h a d d i t i o n a l b a r r i e r s i n c l u d i n g a n A n t e r o o m f o r q u a r a n t i n e i s o l a t i o n .
Protective Environment Rooms
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AIIR rooms are a specialized application of a hospital's HVAC system for Messel, COVID -19, where the airflow supplied into the room is balanced with exhaust airflow to create at least -0.01” Water of gauges negative differential pressure with respect to an adjacent space, usually the hallway or an anteroom.Air-conditioning systems for negative pressure Isolation Rooms should be connected to an emergency power supply to maintain air pressurization in the event of a power failure. The room requires labelling as a negative pressure Isolation Room.
An Anteroom or airlock lobby, when attached to an Isolation room, functions as:A controlled area in which the transfer of supplies, equipment and persons can occur without contamination impacting on the surrounding health care areas.A barrier against the potential loss of pressurization.Controls the entry or exit of contaminated air when the anteroom door is opened.The Anteroom will require sufficient space to allow for storage of Personal Protective Equipment (PPE) i.e. gowns and gloves for protective isolation. Anterooms should not be shared between Isolation rooms.
A clinical handwash basin with ‘hands free’ operation in the Isolation Room and the Anteroom, if provided:
An Ensuite shower and toilet
A self-closing door
100% outside air ventilation (i.e. no return air permitted), with low level exhaust ducts.
Airborne Infectious Isolation Rooms short form (AIIR)
Ante Rooms
Air-conditioning systems for negative pressure Isolation Rooms should be connected to an emergency power supply to maintain air pressurization in the event of a power failure. The room requires labelling as a negative
pressure Isolation Room.
A negative pressure Isolation Room
requires the following:
Type of Pressuriza�on * Isolation Room Anteroom Ensuite
Class S (Standard pressure) Not required
Class N (Negative Pressure) - 30 Pa - 15 Pa - 30 Pa
Class P (Positive Pressure) + 30 Pa + 15 Pa + 30 Pa
Class P with negative pressure Anteroom + 15 Pa - 15 Pa + 30 Pa
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ROLE OF HVAC SYSTEM EQUIPMENT SYSTEM
When designing the mechanical systems to support isolation rooms, the designer must consider not
only the airflow required to maintain the proper pressure differential, but also the location of the equipment, the serviceability of the equipment and equipment redundancy. Depending on the
number and type of isolation rooms in the facility, it is generally more economical to provide a single
larger system to serve multiple rooms than multiple smaller systems.
The same air-handling system that
serves other standard patient
rooms may be used for isolation
rooms.Theair-handling unit serving
the isolation rooms requires
minimum-efficiency reporting value (MERV) 7 pre-filters,with eitherMERV14orhigh-efficiency particulate air (HEPA) final filters. MERV 14 filters are adequate for AII negative pressure rooms and for
PE positive pressure rooms when
terminal HEPA filtration is used at the supply diffusers serving the PE room.
For the exhaust system serving AII rooms, the exhaust fan should be located outdoors, if
possible, and be placed as far
away from intakes and public
areas as practical, but no less
than 25 feet with discharge
above the roof. For outdoor
fans, all exhaust from AII rooms should be exhausted by means of a vertical exhaust stack or exhaust fan with a vertical discharge arrangement.If the
fan must be located inside,
welded ductwork should be
used downstream of the
exhaust fan, and a bag-in/bag-out filter
housing with pre-filters and HEPA filters should be installed upstream of the exhaust fan. The exhaust fans shall be served by emergency power,
and the fans should be labeled
as contaminated air to meet
the recommendations of the
Centers for Disease Control
andPrevention(CDC).and
Prevention.Redundancy of the
equipment also needs to be
considered and will depend on
the facility’s typical census of
infectious patients. On larger
systems serving multiple
rooms, redundant fans are
recommended so the failure of
a single fan does not
compromise the safety of
patients.
A. PRESSURE RELATIONSHIP. B. AIR CHANGE (SUPPLY / EXHAUST AIR).C. AIR FILTRATION. D. TEMPERATURE.E. HUMIDITY. F. AIR MOVEMENT (Supply & Exhaust).
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A negative pressure room in a hospital is used to contain airborne contaminants within the
room. Viruses, bacteria, fungi, yeasts, molds, pollens, gases etc.
A negative pressure isolation room is commonly used for patients with airborne infections like
COVID-19.According to the CDC, a patient known to have contracted the coronavirus can
spread it person-to-person.The negative-pressure isolation room therefore is designed to help
prevent the spread of a disease from an infected patient to others in the
hospital.Negative-pressure isolation rooms require a minimum of 12 air changes of exhaust per hour and must maintain a minimum -0.01-inch Water gauges negative-pressure
differential to the adjacent corridor whether an anteroom is utilized.
When an anteroom is provided, airflow should be from the corridor into the anteroom, and from the anteroom into the patient isolation room.
To maintain the required pressure differential, the exhaust air quantity must always be higher than the supply airflow. Depending on such factors as room size and the room’s heating and cooling loads, more than 12 air changes per hour may be necessary.
These individual control and equipment decisions come together in the designs of the
positive-pressure and negative-pressure rooms. These include:
Positive Isolation Rooms
A positive-pressure isolation room is designed to keep contagious diseases away from patients
with compromised immune systems, such as those with cancer or transplants. These rooms
require a minimum of
a) (a) 12 air changes per hour of supply air & minimum Fresh Air 02 air changes or more
b) Must maintain a minimum 0.01 inch WC positive-pressure differential, ensuring that the patient is protected from airborne contamination regardless of whether an anteroom is used.
A. DESIGN REQUIREMENTS FOR PRESSURIZATION:
B. COVID -19 NEGATIVE PRESSURE ROOMS:
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Typically, a minimum airflow difference of 150 to 200 cubic feet per minute (CFM) is adequate to maintain pressure differential in a well-sealed room.
Temperature of room may be 21 to 24 C depends on the requirement. Humidity should be around 40% to 60%.Exhaust from negative-pressure isolation rooms, associated anterooms and associated toilet rooms must be discharged directly to the outdoors
without mixing with exhaust from any non-AII rooms.
However, multiple AII isolation rooms may be connected to the same exhaust system. The exhaust ductwork serving AII negative isolation rooms also should be permanently labeled as contaminated air within the facility.
An air change is how many times the air enters and exits a room from the HVAC system in one hour.
Room CFM Formula
Let’s look at this engineering formula differently. For example, what if the airflow is unknown and you need to calculate the required CFM for a room?
Here is a four-step process on how to calculate the room CFM:
Step One – Use the above Air Changes per Hour Table to identify the required air changes
needed for the use of the room. Let’s say it’s a conference room requiring 10 air changes per
hour.
Step Two - Calculate the volume of the room (L’ x W’ x H’).Step Three - Multiply the volume of the room by the required room air changes.
Step Four - Divide the answer by 60 minutes per Hour to find the required room CFM:Here’s an example of how to work the formula:
Typical Negative Pressure Isolation Room with Anteroom & Ensuite, showing airflows and relative pressure gradients
AIR CHANGE
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a)acceptable indoor air quality (IAQ): air in which
there are no known contaminants at harmful
concentrations,
b)determined by cognizant authorities, and with
which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.
c)aird)ambient air: the air surrounding a building;
the source of outdoor air brought into a
building.
e)cool air: air whose temperature is less than
the average space temperature.
f)exhaust air: air removed from a space and
discharged to outside the building by means of
mechanical or natural ventilation systems.
g)indoor air: the air in an enclosed occupiable
space.
h)makeup air: any combination of outdoor and
transfer air intended to replace exhaust air and exfiltration.
i)outdoor air: ambient air and ambient air
that enters a building through a ventilation
sys- tem, through intentional openings for
natural ventilation, or by infiltration.j)primary air: air supplied to the ventilation
zone prior to mixing with any locally recirculated air.
k)recirculated air: air removed from a space
and reused as supply air.
l)return air: air removed from a space to be
recirculated or exhausted.m)supply air: air delivered by mechanical or
natural ventilation to a space and composed
of any combination of outdoor air,
recirculated air, or transfer air.
n)transfer air: air moved from one indoor
space to another. ceiling supply: air supplied
to the space more than 4.5 ft (1.4 m) above the floor.
CFM CALCULATION:
Length of Room 12 Feet
Width of Room 12 Feet
Height of Room 08 Feet
Air Change Requirement12 Minimum (ACH)
Area of Room 144 Sq. Feet
Volume of Room 1,152 Cubic Feet
Air Flow 230 CFM
CFM = ACH X Room volume in Cubic Ft / 60
(Min / Hr)
Where
ACH = Air Change Rate per Hour
CFM = Air Flow Rate (Cubic Feet per Minute)
Room volume = Space Volume (Cubic Feet)
DEFINITIONS AS PER ANSI / ASHRAE STANDARD 62.1 - 2019
CFM
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HEPA stands for High Efficiency Particulate Air and is a filtration rating that captures microbes, dust, and particulates down to 0.3 Micron. But what does that really mean and how do they work?The U.S. Department of Energy first termed HEPA as a filtering specification for suppliers of filtration products based on how effective they were at particle removal.HEPA filters consist of a complicated mix of filaments and fibers that carry a static charge which lures various microbes and particles like a magnet.HEPA filters should be mandatory in all healthcare-sensitive environments such as hospitals, clinics, quarantine facilities etc.An interesting study performed by NASA indicated that HEPA filters were able to capture sub-micron particulate down to 0.1 micron!You can view the study here: NASA HEPA Study
The chart (next slide) shows the MERV ratings. It shows particle size ranges. It also shows air filter efficiency levels. Efficiency is measured by the percentage of particles captured.
A MERV rating chart shows a numerical value. The range is from 1 (lowest efficiency) to 20 (highest efficiency).
AIR FILTERATION
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Airborne Transmission
ASHRAE Standard 170 2008/ 2013 or CDC defines for airborne infectious isolation room to supply and return grilles for air flow to protect the infectious particles.Doors should design as per isolation standard room.Windows should be proper sealed.Air Change Per Hour should check coz low means starve and high means turbulence.In clinic and open grocery room – they can use plastic or glass at different points in order to restrict the cough & sneeze and then clean it. Require more study.Please see the video shown for isolation room COVID 19 recently.
Temperature of the room should be design. Normally design 21 C to 24 C.Humidity should be between 40% to 60%.
TEMPERATURE & HUMIDITY
COMMISSIONING & MAINTENANCE
AIR RESTICTION AND SUPPLY & RETURN AIR FLOW DIRECTIONS
https://www.youtube.com/watch?v=qBR-s-a6IaU
1. After construction is completed, but prior to occupancy, the mechanical or balancing contractor typically will adjust the airflow quantities as directed by the design engineer to ensure that the isolation room is operating as Pressure Difference between the rooms. Air Flow directions between the corridor and anteroom, anteroom and patient room.2. Air Flow patterns within the patient room should be tested to ensure that there are no stagnant areas.3. In addition, isolation rooms should be commissioned to prove correct pressure relationships, proper operation of room controls and the functionality of the pressure monitor and alarms.4. Most manufacturers of pressure monitor also recommend that the pressure monitor be recalibrated annually. The results of this periodic testing should be recorded because the authority having jurisdiction may request the data during a survey.5. The tightness of the room should be checked and documented. The containment of the isolation room should be checked and documented.6. In addition to routine testing of the isolation room, the hospital staff who will be utilizing or maintaining the room should be trained on the proper use of the room, including how the pressure monitor works.7. It also can be used to alert hospital staff, if the room is not performing as designed.8. HEPA Filter pressure drop should be checked and documented.9. The maintenance should be checked as per the guidelines for the classification and design of isolation rooms in healthcare facilities:10. The planned maintenance should be scheduled at an interval not greater than 13 weeks and the following items should be checked.11. Air Change Rate.12. Supply Air & Exhaust Air Quantities.13. Terminal HEPA Filters.14. Exhaust Register.15. Room Pressure Gauges.16. Damage to the room interior.17. Supply & Exhaust Fans.18. Room seals and Door closer.19. BMS System, if applicable.The exhaust fan should be located outdoors and placed as far
away from intakes and public areas as practical with discharge above the roof
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CONCLUSION REFERENCES1.World Health Organization
Web Site.
2.NASA Website Link.
3.CDC – The Centers for
Disease Control.
4.Guidelines for the Classification & design of Positive / Negative Pressure
Rooms.
5.OSHA - Occupational Safety
and Health Administration
6.CHT Healthcare
7.BSD Solutions
8.HVAC-ENG Website
9.ASHRAE Handbook 2019 –
HVAC Applications
10.ASHRAE Standard 2016 For
Location of Filters.
11.MERV Table – ASHRAE
12.ANSI / ASHRAE Standards
62.1 – 2019
1.Calculate the load and match the equipment as per
the design requirement.
2.Use HEPA Filters - 99.97% effective of 0.3 Microns.3.Dehumidification.4.Fresh Air as per the requirement of application.5.Minimum 12 ACH requires & minimum Fresh Air 02
air changes or more.
6.Humidification, if require.7.Heating, if require.
8.Room Temp. 70 F to 75 F (21 – 24 C) and RH 40% to 60%.9.Positive Pressure Room or Negative Pressure Room
at least 0.01 inches of water gauge.
10.Exhaust Air should require HEPA filters most of the cases and velocity should be above 10 m/sec.
11.Use plastic or glass shield in the open area such as
entrance hall, clinic area, shopping mall etc to avoid the
spread of droplets.
12.Labelling on entrance of room.
13.Proper Commissioning.
14.Operation & Maintenance as per the guide-lines.
DISCLAIMERThis article is a preliminary finding and guideline all comments and suggestion are welcome to fine tune. Pakistan HVACR Society and the author may be indemnified on any implementation. It is suggested to further investigate before any final execution.