Understanding the 4 Types of Air Purifiers

Due to Covid-19 pandemic, there are rising concerns about the potential transmission of the virus in enclosed spaces such as indoor areas, where air-borne bacteria and viruses can circulate when airflow is restricted. To prevent bad airflow, people are becoming more interested in the air purifying system to lower the risk of getting sick. There are four main types of air purifiers that are used at home .

HEPA Purifiers

The most common one is the HEPA purifiers. High-efficiency particulate air (HEPA) filters capture airborne particles from moving air using a dense, random arrangement of fibers. HEPA filters use the physics of particles moving through air to yank them out of the airflow. Their operation is simple but extremely effective. They have an efficiency of removing 99.97% of particulate matter of size less than 0.3 microns from contaminated air ensuring a flow rate anywhere between 150 -400 cubic feet per minute depending on the clogging of their pores.


Pros:

Reduces allergy and asthma symptoms:

Particles like dust, dander, and pollen that cause allergy symptoms are large enough for a HEPA filter to catch

Commonly available:

HEPA filters are found in a variety of home appliances including whole-house air filtration units, portable air purifiers, and vacuum cleaners.

Produces no byproducts:

Other air purifying products like ozone, ionizers, and PECO all emit a harmful byproduct into the air.

 

Cons:

Won’t remove every particle:

will not remove pollutants from the air that are smaller than 0.3 microns, including viruses, some bacteria, and volatile organic compounds (VOCs).

Requires frequent replacement:

HEPA filters trap most of the particulates in the air. This means they tend to clog faster than more porous filters.

Can be difficult to clean:

The shape and size of your air purifier may make it difficult to access the HEPA filter and clean it.

 

Sources:

The Pros and Cons of Using a HEPA Filter in Your Home Air System

https://molekule.science/pros-cons-hepa-filter/


UV Purifiers

Industrial installation for UV water purification

UV stands for ultraviolet. UV Air Filtration is a specialized way of treating your air that reduces biological compounds.  It can also help eliminate potentially harmful bacteria and viruses from the air. There are special products that can be installed in addition to the current HVAC systems so that the UV air filtration or UV air purification system purifies the air as it is conditioned by your AC and heating system.


Pros:

Elimination

eliminate microscopic elements, such as viruses, bacteria, or mold, that can be toxic or harmful

Silent:

you won’t even know it’s running

Won’t accumulate dirt:

there’s no physical filter

 

Cons:

Won’t remove every particle:

most allergens, dust, or other solids such as cigarette smoke, gases, or other chemical fumes cannot remove.

Require some maintenance:

AirCleaner.org tells us “every year, about 15% of an ultraviolet light’s power is decreased.”

http://www.aircleaner.org/uv-air-purifiers/

By-product created:

When UV purifiers expose air to UV light, the same energy that breaks the bonds of DNA in microorganisms can also split oxygen (O₂), which can reform into ozone (O₃). While beneficial high in the atmosphere, ozone is a dangerous pollution in your home.

 

Sources:

https://www.comfortexpertsinc.com/blog/2015/april/pros-and-cons-of-uv-air-filtration/

https://www.schnellerair.com/blog/pros-cons-what-you-need-to-know-about-uv-air-filtration/


Ozone Air Purifiers

Ozone is a molecule composed of three atoms of oxygen. Two atoms of oxygen form the basic oxygen molecule–the oxygen we breathe that is essential to life. The third oxygen atom can detach from the ozone molecule, and re-attach to molecules of other substances, thereby altering their chemical composition. It is this ability to react with other substances that forms the basis of many manufacturers’ claims.


Pro

more applicable:

applicable for biological contaminants, not airborne inorganic particulates or chemicals

non-occupant settings:

ozone generators can be used to disinfect the air and kill microbes

 

Con

immediately harmful to your health

ozone can damage the lungs. Relatively low amounts can cause chest pain, coughing, shortness of breath and throat irritation.

leaving byproducts:

just as bad or even worse than the original chemicals.

 

Sources:

https://ww2.arb.ca.gov/our-work/programs/air-cleaners-ozone-products/hazardous-ozone-generating-air-purifiers

https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners#intro


NCCO Purifier

NCCO is an innovative technology invented by members of HKUST Entrepreneurship Program. It has been well recognized by the Hong Kong government and the public sector and is a revolutionary air purification technology that will change the world.

In comparison to other air purification technologies such as activated charcoal, UV light and electrostatic precipitator. NCCO is more efficient at removing pollutants. For example, activated charcoal can only absorb but not decompose pollutants, and can only last for a short period of time (usually three months) without replacement. Once the carbon filter is saturated, the pollutants absorbed will be released to the air causing “second pollution”, which can cause great harm to health.

On the other hand, NCCO can absorb and decompose pollutants continuously by combining Active Oxygen and High grade synthetic zeolite, and the technology can last for up to 12 years in a laboratory environment. NCCO has solved a range of air pollution issues in different sectors including commercial, industrial, retail and motor etc. In addition, it can resolve indoor and outdoor air quality problems including pollution caused by PM2.5, PM10, VOCs and formaldehyde. Being able to remove the root sources of pollutants, NCCO acts as an excellent air purifier. Being a proven concept with these capabilities, NCCO is playing an important role in air purification technology development.


Application for NCCO Purifier

fan coil system

Office Ceiling

Lift

 

 

 

 

 

 

 

 

Drone inspection Paradox – Speaking from Professional

Drone application in the view from Professional Surveyor 

As drone technology, or Unmanned Aerial Vehicle (UAV) , becomes increasingly mature and commercialized, the real estate industry has jumped at its potential for building inspection. 

Use of Drone in Construction field / inspection 

Drone technology contributes to the construction field in several ways. It can be used to capture a full picture and provide a solid understanding of the site. It can help in constructing a progress model that assists in monitoring construction process with ease. 

Theory Vs Practical and Professional 

In theory, it is an elegant solution that allows inspection to be carried out on areas that are hard to access. In addition, some IT Engineer alleged that an accurate diagnosis of the building could be be exponentially enhanced by AI. Though, we have had a lot of reservation to this AI application theoretically. However, the actual application of drone technology in building inspection can be less than optimal and costlier than previously believed. Aside from all the hype, it may not stack up against other alternative building inspection technologies and methods.

Professional Surveyor Feedback to Drone application

While UAV can reach areas that are difficult to reach, they have their own physical limitations in professional building surveying. 

Physical Limitations includes:

Hardware Limitations 

  1. UAV has a general altitude limitation of 90m and the image pixel is limited at 1084-2k in most models. The image via the controller is usually compressed for storage, at an even lower resolution. For some inspection which demands close visual inspection, such as sealant shape, cracks on the wall, damp patches mark, deformation of materials, rusty stain etc. The image captured are lust loss and become unreliable. 

Glare from the reflective surface 

  1. Drone operation is heavily dependent on weather conditions. Sunlight can cause glare on reflective surfaces, rendering footage and image unusable. Should there is strong reflective sunlight, the image becomes glared with distorted illusion background . 

Insufficient data for thousand type of variation to build machine learning

  1. AI diagnosis for building inspection is often mentioned as a feature together with drones. AI is built on top of a massive database that promises diagnosis and predictive ability. However, buildings vary by many elements, such as building envelope, height, location, profile, and usage. Furthermore, buildings are dictated by regulations as a product of the location, weather and idiosyncratic factors. There simply isn’t enough data available to power AI to be a blanket solution to building inspection. Currently, professional knowledge is still essential to interpret information generated by AI.

Safety and Lack of Standardization 

  1. There are designated No Fly Zones due to congested buildings, privacy, securities, etc. In addition drones application is not standardized for UAV inspection deliverables. One very rare known limitation is the safety distance between the building and the drone, many drone model is designed to be in hold position when the drone intervenes into the safety distance. This distance makes the image captured ability be doubtful.  

Form over substance

Professional Knowledge is indispensable and cannot be replaced by UAV or AI currently. Having said that, drones can assist Surveyor in capturing images, reference pictures and preliminary scans prior to on-site survey. Unfortunately, it may upset the Surveyor owning to the image reliability. 

Drone application and 360 Cam

Our feed previously posted has presented the 360 Cam for capturing in centimetre distance to the external wall. The image is sent via data to the mobile phone. The inspector can inspect the physical object with the immediate aid of 360 image .

 

Be a smart user to technology 

Always be handy to the technology can advance your professional skill. On the contrary, too much fantasy to the technology will be ended with effort abortive

Building Information Modelling (BIM)

BIM is not new to the architecture, engineering and construction industry, it is a process that takes advantage of design technology to create better, faster, and more cost-effective outcomes. From 2018 to 2020, the adoption rate have surged by over 30% in Hong Kong, so it is the time for us to learn what is BIM and why so many companies adopt BIM.

BIM in Hong Kong: https://www.bim.cic.hk/Upload/publication/87/download_2/b55a28ce365e436292cf0e5de923b09e.pdf

BIM in construction: http://www.convertbim.com/succeed-implementing-bim-process-part-2/

What is BIM?

BIM is not software, but a process. Software is the technological core of BIM, which supports 3D design, intelligent models and information management, but it only represent part of BIM. Another part is social components, including the work practice that utilize software collaboration and coordination. Therefore, BIM represent the process to construct a digital information model for a building.

Common Software for BIM: https://veracityconsultant.com.tw/what-is-bim

BIM is so much more than a design tool, within a BIM process, a project team contribute information and data about a proposed building in a shared digital space. The digital information contributed could include specifications, schedules, performance, requirements, programmes, cost plans, and so on, and of course some drawings. Those drawings are created in 3D, while the non-graphical information is linked to the graphical 3D models, when you explore and click on different parts of the 3D representation, you’ll be able to access the information about it. Clicking on a light for example might give you information on its manufacturer, cost, performance level and when it will need replacing. Hence, BIM is not only for architects, but for all parties that involves in construction.

How to contribute information to BIM: https://www.a2kstore.com/understanding-levels-of-bim

Information linked in BIM: https://www.thenbs.com/knowledge/what-is-building-information-modelling-bim

Why Use BIM?

Executive Director Building Information Management at National Institute of Building Science suggest that BIM cut construction cost by 13% to 20%. A study from the Stanford University Centre for Integrated Facilities Engineering suggested that BIM attribute a 7% reduction in time for project completion.

Construction cost reduce 20%

Construction time reduce 7%

 

In the traditional way of construction, project information is not used efficiently, much information is wasted due to mistrust, do not know what information is available, lack of process and standards as well as information not yet complete. According to the research from U.S. Department of Commerce Technology Administration, in traditional method of construction, the poor use of data coupled with highly fragmented teams cost the US capital facilities industry $15.8 billion annually, 2/3 of which is paid for by the owners. While BIM have clear guideline for information management, it clarifies how to create and share data by stating the requirement for who, when and how they provide data as well as the quality check to be undertaken to ensure accurate data. BIM Adoption Survey 2019 conducted by HK CIC found that near 90% of BIM Leaders in Hong Kong agree BIM enhance communication.

Huge cost for information misuse: https://damassets.autodesk.net/content/dam/autodesk/www/solutions/bim/BIM_for_Owners.pdf

BIM enhance communication

Worse still, 30% of the construction cost in U.S. is paid for rework, for example, the air conditioning duct is designed to go through a load-bearing walls. But since this arrangement only appears in the air conditioning plan, construction workers do not realize it until the load-bearing walls has already been built, they can only change the design in the construction site. From the MacLeamy curve, we understand that the project becomes more costly to change when it is in later stages. A study from the Stanford University Centre for Integrated Facilities Engineering reports that the function of clash detections in BIM resulting in savings of as much as 10% of the contract value.

MacLeamy curve: https://www.cibsejournal.com/cpd/modules/2016-12-bim/

Reduce Rework

Based on the research from U.S. Department of Commerce Technology Administration, in traditional way of construction, more than 60% of the capital invested failed to meet schedule target. For example, in traditional method, cost estimating requires Quantity Surveyors to count components one by one, while BIM software can count itself. A study from the Stanford University Centre for Integrated Facilities Engineering suggested that BIM decrease 80% in the time required to generate an expenditure quote. BIM Adoption Survey 2019 conducted by HK CIC found that over 80% of BIM leader agree BIM enhance time management.

Time and Cost Estimation in BIM: https://clouda2k.co.uk/entering-the-5th-dimension-3d-bim-to-5d-bim/

BIM enhance time management

GBE welcomes comments from professionals and enquiries from the Public.

Cracks in Stone Cladding

Nice Stone Cladding but Danger from Height 

Stone cladding are natural, good-looking and durable, and are widely used in both interior and exterior applications. Although stones are durable, on average, you may not know that there at least is 1 to 2 % of stone panels on buildings in US (Simmons & Richter, 1993) contain cracks due to various reasons.

Example of cracks on stone cladding: http://www.service.hkpc.org/hkiemat/previous/2008/mastec03_notes/SLCHAN.PDF

Common Types of Stones

  • Granite

Most granites are suitable to be used as building materials, as they are hard, dense, durable, virtually impermeable to water, resistant to impact damage and stable within industrial environments. Because of the high cost of quarrying and finishing granite, it is frequently used as a cladding material or alternatively cast directly onto concrete cladding units. Besides, granite is also available for flooring and for hard landscaping including pavings, setts and kerbs.

Granite: https://www.minimegeology.com/granite-igneous-rock-graywhite

  • Sandstones

Natural sandstones can be fine or coarse in texture depends on the nature of the original sand deposit. Some types of sandstones, for instance, Calcareous sandstones, are not durable under acid rain.

Sandstone: https://freewp.cfsscloud.hk/idb/rs024-sandstone/

  • Limestones

Limestones must not be mixed with or located above sandstones, as this may cause rapid deterioration of the sandstone. Some limestones, for example, dolomitic limestone, is more durable then original limestone as it replace calcium carbonate content by magnesium carbonate. Nonetheless, it still cannot resistant to heavily polluted atmospheres.

Limestone: https://www.azomining.com/Article.aspx?ArticleID=1236

Effect of Cracks

The major concern of cracks development on stone slab is the weakening of fracture withstand ability on the maximum wind load of the stone panel. Another concern is that cracks may diminish much water exclusion properties of the of sealer applied on the stone surface. The effect of cracks will eventually contribute to highly undesirable appearance effect and worst still , the safety issue for instance, corrosion of anchors. Other effects includes aesthetic qualities and durability of the stone.

Stone cladding falls from the building facade: https://www.researchgate.net/figure/Examples-of-stone-slabs-removed-from-the-building-facade-a-east-side-b-south-side_fig4_336970581

Types of Cracks

  • Natural Crack

Natural cracks are formed by geologic processes in the stone before it was quarried, hence, natural cracks are most likely more than several million years old. Some natural cracks appears to be artificial cracks, so natural cracks are recognized by the presence of natural crystal. Natural cracks are ubiquitous in some granites, 1 to 2 dozen may occur within an area of one square foot. When liquid, for instance, sea water and rain, makes its way through the clefts and dispense minerals into the crack, crystals formed. Although natural cracks are common in stones, not all of them weaken the stone, only some severely decrease the strength of stone.

Natural cracks: https://www.123rf.com/photo_98560883_red-granite-slab-with-a-deep-crack-natural-stone-texture.html

Natural crystal in natural cracks: https://tinyrituals.co/blogs/tiny-rituals/pyrite-meaning-healing-properties-everyday-uses

  • Exacerbated Natural Crack

Exacerbated natural cracks are natural cracks that have been widened or lengthened by non-geologic activities. They are recognized by its width and length exceeding the value expected for a natural crack.

  • Artificial Crack – Crack developed other than by natural process

Artificial cracks are formed by non-geologic processes. They appeared to have sharp edges on polish face, irregular walls and do not have well developed crystal. If artificial cracks are located in or near mid-span, they can severely decrease the strength / durability of the stone panel.

Artificial Crack: https://www.cnilawfirm.com/specific-construction-components-gallery/

Professional Building Surveyor pay attention to the “Causes of Cracks”

Cracks formed when the local stress of stone is larger than the local strength. The reasons increase local stress includes geological processes, quarrying, handling, fabrication, and erection. Each kind of reasons carries a ton of knowledge behind. Besides, residual stress may also be a major factor in the development of cracks, source of residual stress includes handling, fabrication, shipping, dunnage, and erection on the building. The most typical is the “erection” problem

 

  • Geological Processes

Stones experience heat and cold cycles repeatedly, in heat days, the stone expands while in cold days, the stone contract. The repeated thermal expansion stresses tend to open cracks along grain boundaries.

Cracks: https://www.champlainstone.com/stone-101/

  • Quarrying Process – Fine flaw hidden in the slab block 

stone can be damaged in the quarry if it is extracted by the use of explosives which may cause internal fractures and cracks.

 

  • Handling and Fabrication

damage can be caused by excessive tooling of the surface of the stone, it may cause hairline cracks.

 

  • Dry fixing / erection

If the workmanship or the installation of the stone cladding is too not strictly controlled, mal-anchorage may cause the hairline cracks will be easily found near the anchor point.

  • Shipping – Storage of inventory 

Granite slab should avoid being carried flat . The localised stress building up due to unduly surface may cause hairline granite crack. Examine the stone finishes before hanging on the wall is highly important

  • Dunnage

Dunnage is used to protect stones during shipping, if unsuitable material are used, for example, softwood, the stone may slide around and form cracks or damage.

 

Quality Control before Installation

Before installation, materials should be inspected according to the construction quality acceptance specifications and design requirements, for example, have factory certificate, inspection report, material mechanical properties test and stone radioactivity. On site witness sampling and sampling inspection can also be conducted. The variety, color, pattern, flexural strength, tensile strength, compressive strength and common defects of the stone tile should be checked.

Inspection

 Inspection Method Related Defects
Crack Meter/ Crack Comparing Device/ Optimal Measuring Device, Mechanical Extensometer Fracture, Cracking, Cracking or fracture of the stone element near the joints
Cladding Flatness and Slope Evaluation Vegetation, loosening of the stone element, non-linearity or inadequate dimensions of the joints, cracking or fracture of the stone elements near the joints
Measurement of Internal Humidity Level Biological Colonization, alteration or deposition, cracking or fracture of the stone element near the joints
Percussion Test

 

Loss of adherence of the stone element, flatness flaws of the cladding surface, Gap in the stone

 

Cladding Flatness and Slope Evaluation: https://link.springer.com/article/10.1007/s00170-019-04893-7?shared-article-renderer

 

Tapping rod for percussion test: https://shopee.com.my/TAPPING-ROD-MOSAIC-TESTER-TILE-TESTER-TILE-CHECK-EXTENDABLE-HOLLOW-WALL-HAMMER-CHECKER-HOLLOW-EXAMINER-TILES-CHECKING-i.53165988.1957429999

Maintenance – Cleaning

External granite and marble cladding require regular washing with a mild detergent solution. For example, highly polished external marble should be washed at least twice per year to prevent permanent dulling of the surface.

Cleaning: https://www.industrial-clean.co.uk/services/brick-and-stone-cleaning/

 

In short, although stones are durable, regular inspection and maintenance are required to identity the effect of cracks one by one and to distinguish whether maintenance is required.

GBE welcomes comments from professionals and enquiries from the Public

 

References

Simmons G., Richter D. Cracks in building stone. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1993, 30(7): 1553-1557.

Exposure on Elevator Ride is full of air-borne transmission

Top News

Otis Worldwide Corporation (NYSE: OTIS) released the results of a three-month academic study that investigates how elevator airflow affects potential exposure to the COVID-19 virus and a science-based approach for how to mitigate that exposure in elevators.

Findings show the significant amount of air exchange present in most elevators combined with simple mitigation strategies, including all riders properly wearing a surgical-style mask and the installation of a common type of air purification system, puts an elevator ride on the lower end of the exposure spectrum.

The study indicates strongly the provision of air purification system inside the lift car reduce the airborne transmission

MITIGATION STRATEGIES – VENTILATION CAN REDUCE RELATIVE EXPOSURE EVEN FURTHER

The study was led by Dr. Qingyan (Yan) Chen, the James G. Dwyer Professor of Mechanical Engineering at Purdue, who is widely recognized for his research into the spread of infectious disease through indoor air systems – and how to prevent it.

“Air exchange is important. the study findings concluded that the higher ventilation in an elevator, relative to the compared activities, results in lower exposure opportunity. If all passengers properly wear masks, the relative exposure risk drops 50%. Air purification, called NPBI, can reduce this by an additional 20-30%,”

Source: https://www.otis.com/zh/hk/news?cn=otis-releases-elevator-airflow-study-findings-covid-19-exposure-on-elevator-ride-is-low-risk-with-simple-mitigation

RISK OF CONTAMINATION IN LIFT CAR – PISTON MOVEMENT CREATES THE AIR DRAG

The study further investigate the position of the air inlets and outlets relationship. Alike to our another presentation 2021 and the study-2008 by University of Hong Kong, the position of inlet/outlet does significantly influences the flow circulation and droplet dispersion.
An air purifier does not eliminate airborne transmission. The droplet dispersion is reduced when a pair of an inlet and an outlet is implemented. The overall practical conclusion is that the placement and design of the air purifier and ventilation systems significantly affect the droplet dispersion and AVT. Thus, engineering designs of such systems must take into account the flow dynamics in the confined space the systems will be installed.

 

Source:https://aip.scitation.org/doi/10.1063/5.0038180

VENTILATION & AIR PURIFICATION SYSTEM SELECTION

(NCCO installation by Kingclorence)

The ventilation inside the Elevator is governed by legislation and code of practice from EMSD. It will be great if the position of inlet / outlet may be given due consideration in term of droplet dispersion and aerosol. Thus , in the absence of retrofit for outlet / inlet , the quick fix is to install the air-purification machine which can encourage the positive air flow.

There are different types of air purifiers in the market which can kill virus and improve air quality of the indoor environment. The size of your room is an important factor for choosing a suitable Air purifier. Bigger spaces will need larger air purifiers so make sure you choose an air purifier that can operate in a space that is 20-40% larger than the room for the best performance. GBE offers site inspection services for air quality control and recommends the air purifier for your best suit. Please contact us for more details.

Thank you

 

COVID-19 Outbreak From Fitness Centre and Restaurant

Top News

Call it an oversight or yet another loophole in social-distancing measures, but Hong Kong is again gripped by a serious Covid-19 outbreak. Centred on a gym in Sai Ying Pun, the cluster on Friday accounted for 47 cases that contributed to a dramatic surge in the city’s daily number of infections to 60.

Whether it heralds a fifth wave of the epidemic, as some experts are suggesting, is irrelevant; what matters is that for all our experience with the disease, a foolproof approach to containing its spread has still not been formulated.

The super-spreading event at Ursus Fitness seemingly resulted from instructors and customers not wearing masks. They were not required to; authorities had exempted people from wearing masks if doing vigorous exercise, even in indoor public places.

This is despite Covid-19 being spread by people exhaling and that being more pronounced when they are exercising. Belatedly, the government has reinstated the requirement of mask-wearing. All gym staff in the city have been ordered to have a coronavirus test by Sunday.

The oversight has been highly disruptive; in addition to the staff and customers who have tested positive and the gym’s closure for deep cleaning, 240 people who visited recently have had to be quarantined. Some were believed to be bankers, lawyers and educators, and offices and colleagues have been affected.

Source: https://www.scmp.com/comment/opinion/article/3125297/hong-kong-gym-outbreak-again-underlines-need-exercise-caution

VENTILATION IS KEY TO FIGHT COVID-19 TRANSMISSION

Source: https://www.scmp.com/news/hong-kong/health-environment/article/3123251/hong-kong-expecting-around-20-new-coronavirus

According to The Wall Street Journal, after urging steps like handwashing, masking and social distancing, researchers say proper ventilation indoors should join the list of necessary measures. Health scientists and mechanical engineers have started issuing recommendations to schools and businesses that wish to reopen for how often indoor air needs to be replaced, as well as guidelines for the fans, filters and other equipment needed to meet the goals.

Source: https://www.wsj.com/articles/key-to-preventing-covid-19-indoors-ventilation-11598953607

The above videos show how airflow can be visualized without a mask.

Ventilation System to Become an Integral Part Property Grading

Office interior with white columns and panoramic windows in modern loft. Many green plants in pots in workroom with laptops on tables with chairs and cups at daylight, flat lay, nobody, free space

The latest outbreak served as a dire warning for Hong Kong. Covid-19 shined a harsh light on how ventilation can impact business continuity and endanger capex investment. Ventilation provision has become a strict prerequisite for businesses that comes before any initial capital investment and expenditures in order to ensure business continuity.

Which operation demands ventilation

Obviously, all operations require ventilation, but what the standard of ventilation is and how to achieve it? The laws involved are from Schedule 2 of Public Health and Municipal Services Ordinance (Cap.132) and the Buildings Ordinance (Cap. 123). The former legislation is to control “SCHEDULED PREMISES” where crowded space is anticipated while the latter legislation deals with office space.

Second Schedule
[ss. 2, 93 & 102]
Scheduled Premises
(Format changes—E.R. 4 of 2019)


Class of premises
No. of cubic metres per hour for each person who may be accommodated in the premises
Cinemas
13
Dancing establishments
17
Factory canteens
17
Funeral parlours
17
Restaurants
17
Theatres
13

Air Supply Vs. Air Change

The current standard enforced in ventilation in office buildings is the volume of “air supply”, not numbers of air change. There is a huge difference between these two concepts. Air change, which is repeatedly mentioned by the microbiologist, is NOT mentioned by the law.

Massive ducting is needed for air change results no incentive for better system

To achieve the required air change standard, the ducting quantity and sizing is likely almost double than that of normal air supply provision, making it almost impossible for many offices and premises to achieve. Developers are used to providing the minimum standard as required by the law, and not catering to users nor designed for preventing viral outbreak.

Proper Air Treatment System is the Silver Shield

Along with WFH, Social Distancing is an implied feature of our society today. With the slow adoption of the vaccine due to issues stemming from logistics and mistrust, we can expect that limitations on physical gathering may still be in place for the better of 2021. This means that businesses and schools may experience intermittent closures, and productivity technologies such as Zoom will become a more permanent part of work.

Creating indoor air circulation system with Air Treatment

Source: https://www.wsj.com/articles/key-to-preventing-covid-19-indoors-ventilation-11598953607

While air change with external air involves substantial ducting engineering, many operators may consider building the internal circulation system to significantly improve the air quality. There are different types of air purifiers in the market which can kill virus and improve air quality of the indoor environment. The size of your room is an important factor for choosing a suitable Air purifier. Bigger spaces will need larger air purifiers so make sure you choose an air purifier that can operate in a space that is 20-40% larger than the room for the best performance. GBE offers site inspection services for air quality control and recommends the air purifier for your best suit. Please contact us for more details.

See How Strategic Air Purifier Placement Reduces COVID Virus Spread Within Music Classrooms

Air Purification System Selection

 

There are different types of air purifiers in the market which can kill virus and improve air quality of the indoor environment. The size of your room is an important factor for choosing a suitable Air purifier. Bigger spaces will need larger air purifiers so make sure you choose an air purifier that can operate in a space that is 20-40% larger than the room for the best performance. GBE offers site inspection services for air quality control and recommends the air purifier for your best suit. Please contact us for more details.

 

Visual Information Technology in Surveying and Engineering Industries – Part 2

The coronavirus pandemic has affected most of the people around the world. After one year of affection, people started to change their work habits and business model in order to suit this unexpected situation. Work from home(WFH) become the most common arrangement for millions, increasing numbers of people had been saying goodbye to their office. Thanks to communication technologies like skype, Facetime, Slack, Zoom, Google Hangouts and etc; people can still connect and communicate with each other. However, for surveying and engineering industry, inspection or measurement are still necessary work on site. Today we are going to look through how technology may help our architects, engineers, surveyors and all stakeholders to inspect and work throughout the visual information.

Brief History of 360 Panorama

Virtual reality, aerial panorama and 360 panorama are great technologies to use for providing information to all stakeholders. In 1826, Joseph Nicéphore Nièpce invented photography; he took the first photo in the world for more realistic visual information.

 

Credit: https://www.bygonely.com/bg_item/photography-1793-by-joseph-nicephore-niepce/

After the photography was invented, the first panoramic photo camera has invented since 1843. Here is the vintage panoramic photo taken by George Barnard in 1864 which can show clearly and more information throughout the photo.

 

 

Credit: https://www.loc.gov/resource/pan.6a00039

Evolution of Action Camera

Thanks for the technology so far, action camera can take panoramic photo in one single shot. The first GoPro camera was launched commercially in 2004.

 

 

Credit: https://media.techeblog.com/images/first-gopro-camera.jpg

With GoPro evolution, action camera is a suitable camera in all extreme condition which is the best tool for inspection. However, for either filmmaking or inspection; more visual information which help the editors or inspectors easier to get the information. Therefore, people use the action camera for 360 films or 360 photos

 

Evolution of GoPro Action Camera

Credit: https://cheesycam.com/first-problems-with-gopro-hero4-4k-camera-dangerous-battery/gopro-evolution-original-hero-hero2-hero3-hero3-plus-hero4-4k/

GoPro Omni 360

Credit: https://vrscout.com/news/gopro-360-omni-camera-rig-on-sale/

 

From Action Camera to 360 Camera

As the spherical 360 panoramas taken from the GoPro device above still need to use the software to align and edit. It is such a time consuming work flow and not easy for normal people. Luckily, Ricoh has latched their first 360 camera which is the world’s first commercially available spherical camera. This camera become the best tool for inspection which is easy to use and edit in order to get the information.

 

 

Credit: https://theta360.com/en/

Ricoh Theta Sample Photo

 

GBE used both Mi sphere and Insta 360 One X as our inspection tools for visual inspection which the 360 camera helps all stakeholder easy to review the footage and capture the information throughout the image. Here is our first YouTube clip for using 360 camera in our inspection project which give a brief idea of how 360 camera can provide information.

MI Sphere Camera

Credit: https://qwertyarticles.com/2018/06/30/the-world-seen-from-360-degrees-a-mi-sphere-camera-review/

 

Insta 360 One X

Credit: https://www.insta360.com/hk/product/insta360-onex

Visual Information from 360 Camera

By using the software provided by 360 camera manufacturer, the stakeholder can easily capture and collect information from the footage which can easily work remotely and share information to collaborate with others in every project. Here are the sample of the GBE project for you guys to have some idea how the picture can be capture through the software.

 

Here are other sample photos captured from Insta 360 One X

 

In next chapter, we will go through the 3D virtual space by using the latest technology and 360 camera in our industry for visual information.

Visual Information Technology in Surveying and Engineering Industries – Part 1

Visual information is always the most direct way for human beings to understand and explore the world. In the past, human beings used drawings for recording history and details. All this visual information can help people nowadays to understand the information and imagine the visual world.

Image is one of the most important records in both surveying and engineering which used for monitoring the progress and review the findings throughout site inspection. More photo records which will help to indicate more details refer to the drawings. Therefore, a good practice of site inspection; photos taking is always a key factor which may affect the progress and follow up actions for all projects.

Importance of Visual Information

According to “YourStory”, humans are wired to respond to visuals more than just text. As visual content is easier to consume and digest.

  • Around 50-80 percent of the human brain is dedicated to visual processing such as vision, visual memory, colours, shapes, movement, patterns, spatial awareness, and image recollection. (Reports The Wiley Network)
  • Visuals with colour increase people’s willingness to read a piece of content by 80 percent. (Reports – Saurage Research)
  • If you hear a piece of information, you might remember only 10 percent of it. Adding a picture to that results in a rise of recall up to 65 percent. (Source – Brainrules.net)
  • Posts inclusive of images produce 650 percent higher engagement than text-only posts. (Source – Pinterest)
  • It takes only 150 milliseconds for us to a process and image, and then another 100 milliseconds for us to attach any meaning to it. (Reports – Canva)
  • People following directions with text and illustrations do 323 percent better than people following directions without illustrations. (Source – Pinterest)

Credit: https://yourstory.com/2018/04/scientific-reasons-visual-marketing?utm_pageloadtype=scroll

Credit: http://www.iscribblers.com/infographics/5-scientific-reasons-people-are-wired-to-respond-to-visual-marketing/

From Drawings to Photography

As visual information is so important for humans in learning process. Our ancient used drawings to record the history since stone age which helps us to understand the past.

Credit: https://vestnikkavkaza.net/upload2/2017-01-13/180b9ee15b8c4384cd6b36e2cd51c377.jpg

Panoramic drawings become more popular which gave people a great impression for easier understand the information that painter want to deliver. Famous panoramic drawings can be found worldwide, such as “Along The River During the Qingming Festival” (China), Barker’s London panorama of 1792, from the top of the Albion Mills (UK).

Credit: https://upload.wikimedia.org/wikipedia/commons/d/d9/Panorama_of_London_Barker.jpg

Credit: https://www.youtube.com/watch?v=mwMwDYEfMy0&feature=youtu.be

Drawing is a good source of visual information that can record the moment and reflect the details; however, drawings completion may lead a long time to complete and all details are from painters’ memory only.

Photo is another good source for recording and faster in the workflow. Photography technology and also computer software have been developed into a next-generation which help all stakeholders to study and learn deeply with site situation. Location, time, measurement information are also be able to capture by today’s technology.

In the past, film cameras are used for photo taking which will be limited due to cost and photography skills by the site staff. Most photos taking will be either whole shot and defects, not enough details can be shown in those photos.  Since photography technology has been improved a lot, the digital camera has taken the industry practice to the next generation. In the same situation with drawings, people always want to take more details in one shot in order to show more information and surrounding.

A panoramic view of the construction of the ESO Supernova Planetarium & Visitor Centre.

Credit: Architekten Bernhardt + Partner (www.bp-da.de)

With the aid of technology, split-screen panoramic photo comparison enables remote stakeholders to check and communicate with each other remotely in the same platform. Such technology can resolve conflicts and misunderstandings during the construction process. Those photo records can also be stored for facilities management to use for repair and maintenance purposes.

In the next chapter, we will go through more new technologies to show how the new cameras can help in site inspection and measurement.

 

 

“Common Staircase” shared by adjoining lot in Hong Kong

The leftover structure coming from rapid Urban redevelopment in Hong Kong

In the urban development , the land was delineated by “Block” and was subsequently craved or partitioned in a different section and eventually further craved into different sub-section. It resulted a lot of common boundary to each piece of lands adjoining to each other.

 

The common boundary bought in the typical implication of “party wall” and “common staircase”. There was a blog written by GBE about “party wall”. The reader is welcome to comment. “Common staircase” is what this article goes deep.

 

The main staircase of the building became as “common” because it was commonly shared between two pieces of land. The common staircase was jointly owned for the enjoyment of the entire building. Since it was common to two adjoining pieces of land, it naturally positioned at the boundary line. It was not a must but naturally came up in the middle between two lots.

Redevelopment and remaining common staircase

With the re-development took place in one piece of land, the adjoining land where the original main building sitting on was necessitated to maintain the common staircase for access. This came up the situation alike to the “Party wall” where the common staircase needs to be retained and still occupy land and space on the land going to be redeveloped.

 

The first and immediate concern is obviously the common staircase is an enclosed space and fall into the definition of GFA. Nevertheless, this common staircase is nothing helpful and undesirable to new development. To cope with this, the above-extracted part plan has illustrated the example of how the PNAP ADM -2 resolves the GFA problem. In short , the entire footprint of the common staircase be deductible from the GFA calculation. According to PNAP ADM-2 from the Buildings Department, the existing common staircase for an old building can be excluded from site coverage and plot ratio calculation.

 

Case Study in two adjoining Urban buildings

Building “A” was redeveloped in 1992. The landlord was obligated to leave the common staircase un-touched and exempted its footprint from accountable GFA. Building “B” was subsequently redeveloped in 2008, but the redevelopment of Building B has demolished partly the “common staircase” sitting on the respective piece of land.

Ground Floor Plan of Building A (showing the Location of Common staircase with Building B)

 

 

GFA Calculation of Building A

 

Ground Floor Plan of Building B (showing the Location of Common staircase with Building A)

 

 

Site Area Calculation in Building B

Another example showing the common staircase issue

Building “C” was redeveloped in 2004, while Building D was redeveloped in 1994. Building “C” and Building “D” retained the common staircase after both redevelopments.

Ground Floor Plan of “Building C”

Ground Floor Plan of “Building D”

Funny interesting maintenance issue

The interesting things come up is that building A which developed earlier than Building B was containing the old “common staircase” . This old left-over common staircase in Building “A” was not GFA counted by the time of redevelopment. The owner of Building A is caught in dilemma. The site where building A sitting on has fully exploited its GFA potential by the time of its redevelopment in 1992. It is now found no surplus GFA be able to assign to this leftover physical ” common staircase” space in the hope to light up again the space utilisation, particularly valuable in highly urbanised city area. The landlord of building A is naturally no incentive to maintain nor convert this common staircase to other proper usage. The only value is the external wall of the left-over common staircase which was being poised for signage in Building “A” (as shown on the photo below. Obviously, the author is wondering the maintenance liability to the grandfather jointly owned structure , i.e Common staircase

 

Part 2 : Coating materials for Aluminium cladding – Misery of “Self-cleaning”

Following with our part 1 discussion, we now share another hot topic about coating applied on the aluminium. “Self-cleaning” is indeed a merchants’ name . The behind sciences are varying from among different manufacturer. We have conducted some comparison among different materials being applied to the cladding surface.

Theory of “Self-cleaning”

Self-cleaning : Hydrophilic approach 

In short, there are a few theories behind the “self-cleaning” . One typical approach is to create the surface which reduce the water surface tension. When the water droplet lands on the surface, the water droplet has formed an wetting angle to the surface of cladding. The stronger the water tension, the more acute the wetting angle is. The below diagram explains the wetting angle and how it carries the dirt / stain / attachment on the surface. Different manufacturer has formulated different chemical materials to reduce the water tension and flatten the wetting angle. The water is to carry and flush away the dirt. The most typical chemical approach is to create the coating surface which offer better hydrophilic (hydrophilic is origin from latin word, the word philic means love).

 

 

Self-cleaning : Photo-catalytic Oxidation 

Another theory is by “Photo-catalytic Oxidation” . We are not Chemist and cannot cite the theory . Nevertheless, we found one extract from “Chemosphere 193( 2018-198-206)” ,  there explains the “photo-catalytic oxidation” with the below graphic. In short, it is the oxidation process to the VOCs by UV and Photon. This is again alleged by many peers as ” self – cleaning” , but obviously the theory is very different from “hydrophilic approach”

Self-cleaning : Hydrophilic approach

To the contrary of “Hydrophilic” , some manufacturer applied the opposite ; hydrophobic approach. The theory behind is to keep the strong water tension of the droplet and let the droplet to “PICK” the dirt away. From our very preliminary scanning , this technique was more relying on the water – repellent nature ,

Product in the market : – 

We have encountered different approaches in the market. All suggest their “self-cleaning” properties. We try to cite some examples to illustrate different theory behind . We are not in the position to comment each performance and indeed it is difficult to do comparison. We hope this articles can offer some ideas for future research

Kansai Paint : 

One of the product is made by Kasiai, we were given the understanding that the materials is silicon-based modified resin materials with their own additive untold to the public. This is to create the “Hydrophilic” by flush and deliver the dirt.

 

 

Hydrotech from TOTO

Hydrotect is the tradename by TOTO. We extract their self-allegation from their official website. In short, they claimed their coating technique is photocatalytic which is to OXIDE the VOCs in the air. Their website further suggests this “Hydrotect” can offer the hydrophilic surface to flush the dirt

XX Sheet film paper 

A manufacturer , named to be untold here, claimed that there film sheeting offer the self-cleaning. We cannot identify their theory online. Nevertheless, we did a quick water spray test on the surface. We noticed that the water droplet kept intact on the surface and did not appear wetting pattern which is for flushing the surface.  From the picture below, the water – droplet keeps visually keeps the sharp and the droplet drip pattern is in the form of line.