Masjid Al Haram in Makkah hosts the world’s largest heating, ventilation and air conditioning (HVAC) system. The system is provided by “Al-Salem Johnson Controls” also known as “YORK” who maintain Masjid al Haram’s many York multistage centrifugal chillers. It was recently reported that their systems “ensure 100% fresh air” inside Masjid al Haram.
With Umrah on hold and many speculating Hajj could even be cancelled, such news is sure to raise the hopes of Muslims who have had to endure scenes of Masjid al Haram empty. Due to my role at Hujjaj.co I have taken keen interest in the many steps being taken at Masjid Al Haram to protect pilgrims. This article explores the question, would HVAC systems be the solution to crowded areas such as Masjid Al Haram?
With air conditioning systems such as HVAC there are two factors to consider. Firstly whether the air blowing out of them will cause air droplets to fly from infected people, who are in front of the blowing air of the air vents, towards uninfected people and infect them. Secondly the quality of the air being then recirculated.
The First: Air blowing from Air Conditioners
Traditional Air Conditioners may in fact spread Covid-19, as it has emerged that in Wuhan, the epicentre of the outbreak, 9 people had become infected in a restaurant due to air conditioning. A Covid-19 infected person sat near an air conditioning system, as a result the air blew from him further than usual due to the power of the air conditioning, causing the other four people at his table to become infected, as well as 5 people on neighbouring tables.
The restaurant’s air conditioning system was in line with three tables. It was directly behind a table of uninfected people (C in the diagram below). Air blew from this table to a second table (A) where the infected individual was sat, the air then continued from him to the last table (B). The air then circulated due to the power of the air conditioning back to the original table (C) with infected particles present. This caused people at all tables A, B and C to become infected.
Coronavirus Covid-19 is transmitted by respiratory droplets which are 5-10μm. This means the maximum that a droplet should be able to travel is 1 meter. The tables in the Wuhan restaurant were all 1 meter apart, so the air circulated from tables C, to A (infected), to B, and back to A and C as shown in the diagram above could not have occurred in the absence of Air conditioner. The power from the air conditioning has been identified as the likely reason to have blown infected particles significantly further than normal.
The Second: Return and Supply Separation
HVAC systems are different to standard Air conditioning systems as they maintain indoor air quality.
In early April, YORK had discussed the need for internal air purity. Maher H. Mousa, Director of product management at YORK said many people worry due to risks of infection outdoors, but “the pollutants found inside buildings and closed public areas should concern us just as much”. He said the need is even more pressing due to the Covid-19 pandemic.
Mousa also boasted that YORK’s systems hinder disease transmission in crowded areas. He explained the filters they use “achieve up to 95 percent filtration efficiency in comfort application, and 99.95 percent in medical application”. They system itself ensures air purity by taking internal air and constantly replacing it with air from outdoors.
The “Federation of European Heating, Ventilation and Air Conditioning Associations” (REHVA) released guidance on Covid-19 which states that virus transmission via HVAC systems is not an issue if the systems are fitted with “a twin coil unit or another heat recovery device that guarantees 100% air separation between return and supply side”
It is not clear whether these factors are present in the state-of-the-art YORK systems present in Masjid al Haram, but if they are it removes the risk of virus particles being taken in and recirculated.
A concern
The concern still remains that an infected person, sitting in line with the airflow from the HVAC system, would transmit infected particles to people behind him simply through breathing. These particles, as shown in the restaurant in Wuhan would be able to travel further than the standard 1 meter making social distancing redundant. The other people in the restaurant in Wuhan, who were not in the line of airflow, did not catch the infection at all
The administration of Masjid Al Haram has spared no cost when dealing with Covid-19. The mosque recently completely closed off in order to inspect all the YORK systems present. Everything was thoroughly inspected and a deep clean took place.
Saudi authorities have also trialled sterilisation gates at the Gates of Al Masjid an Nabawi, Madinah. The gates are understood to be like isolation pods which clean contaminants from the clothing of the user before they enter the Mosque. Similarly the temperature of everyone entering Masjid al Haram was taken.
Social Distancing
None of these steps ensured that the breathing of an infected person would not pass to uninfected pilgrims, except the forced social distancing put in place by authorities. All worshippers were ordered to stand at least 1 meter away from each other at all times including during the prayer.
This seems to be the only way to ensure that infected pilgrims do not infect other non-infected pilgrims. The other steps such as air purity, sterilising pilgrims as they enter, checking their temperatures, not allowing any food or drink help to support this.
Will Hajj 2020 Go Ahead?
In the capacity of my role as CEO of Hujjaj.co I have not heard any news regarding Hajj 2020. Authorities are preparing themselves for Hajj in case it is allowed but no statement has yet been made if it will go ahead and if so in what capacity.
Hajj could take place for locals only, or it could see drastically reduced numbers of people coming in from around the world who are not at high risk, or it could be opened in some other way.
An announcement is expected this month. If Masjid al Haram is to open any time soon, it will be interesting to see what steps are taken by the authorities as YORK.
