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.

 

Turning Non-domestic space to Domestic usage for Public Rental Housing

To boost the housing supply is the urgent needs in today HK. Although many resources such as transitional housing and new town development are allocated , GBE has been working on two interesting cases which are to convert the “non-domestic space” to domestic usage. We love to sharing our experience to all reader.

Technical Hurdle for conversion 

There are many technical consideration to the conversion. To list some, the issues cover the “GFA” , “site coverage”, natural lighting and ventilation, open space, Fire safety are all in the radar . On top of this , some tricky issues such as concrete cover ; width of re-entry for open space; barrier free access ; provision of gas aperture , Kitchen, sanitary fitment and the clear headroom for the domestic space are all counting on.

Overcome the hurdle

It is technically complex to resolve all the issues in one scheme. We have to prioritise the amount of effort to resolve each problem. Honestly , some of the technical hurdle may be too costly to resolve or even not possible to overcome

  • GFA and site coverage is the most tricky

Among all the hurdles, the GFA and site coverage are the most pertinent and profound factor. We have had a blog talking about the GFA conversion. Honestly , in the case of conversion, we usually have to rebuild the entire GFA calculation and site coverage from scarp. It boils down to the classification of site, open space and roof cover area. It is highly tedious but technical process.

  • Lighting and ventilation / fire safety 

Many peers usually have the impression that these are resolvable and always undermine the inherent difficulties. Let us share you one point, the importance of the RHS and prescribed windows are always in the play. Since the RHS is dictated much by site surrounding and site boundary, it eventually restricts the design of light/ventilation very much

The same hurdles happens to the fire safety. Some of the professional may overlook the essence of the concrete cover and believe the fire proofing materials be helpful. Unfortunately , the clear headroom of the space is always very limited and the resulted headroom after the new fire protection layer added may lead to inadequacy, it sounds ridiculous but it did happen.

  • Sanitary Fitment and Kitchen 

These are not usually posing difficult , but the problem raised from the gas aperture for the bathroom, the RHS for kitchen and the drainage provision for the sanitary fitment. The gas aperture’s design demands a lot of the space consideration while the kitchen needs the RHS. When all these factors come together, the layout of the apartment becomes quite challenging

Looking forward to the future

While a lot of resources have been allocated to MiC , Transitional housing and New town development , we can see there are some abandoned or under-utilised space in urban area , which can be converted into the habitation purpose. We have attempted successfully such conversion in some old districts in Hong Kong. We hope we can bring more similar cases for sharing in future

 

Click here to know more about building defects!

There is always an indispensable relationship between buildings defects, structural stability, and public health. In general, non-structural cracks, structural cracks, concrete spalling, defective external wall finishes and water seepage, etc can be the common types of building defects, which can be easily found in buildings in which do not receive proper maintenance and repair.

Photo showing concrete spalling from the ceiling

Photo showing cracks inside staircase

Photo showing concrete spalling

Photo showing external wall tiles was found missing

Today, as a surveyor graduate trainee, I want to share some causes for the development of building defects. There can be a combination of factors in causing the above-mentioned defects. All property will face some sort of defects during its life span. As a surveyor graduate trainee, we shouldn’t solely focus on the physical look of building defects, we need to observe the surrounding environment and the actual usage in concluding the cause of the particular building defects.

Design, material, construction, usage, and maintenance are the common angles in diagnosis the causes of defects. Taking concrete spalling as one of the examples, given the design stage, when the building is located near the sea, the chloride attack raised from the sea may corrode the steel bar. With the corrosion of the rebar, the volume of rebar inside the concrete will expand 8 times. Crack and concrete spalling may be found.   At the same time, concerning the construction stage, the high water-cement ratio may bring void for the concrete surface due to the increase in permeability, which has the potential possibility to enhance the corrosion of rebar (you can refer to the blog from GBE dated on 28 June 2020). From the above reasons, we understand that the building defects may not be caused by a single reason only. It is the responsibility of the professional to conduct a detailed building inspection before jumping to a conclusion.

Photo showing the stage of rebar corrosion (retrieved from structural engineering blog)

Water Seepage is also a common building defect in aged buildings. The sources of water may come from rain, groundwater, element, condensation, plumbing, drainage, and user activities. When we observe some symptoms like water stains, water dripping, rusty stains, peeling of paint during the inspection, suspected water seepage maybe happened. Before diagnosing the source of water seepage, a preliminary desk study is required (if you wanna know about the details of desk study in how to tackle the annoying issue comes from water dripping in the living area, you mustn’t miss the blog from GBE dated on 4 Jan 2021). We may need to collect some background information like the location of dampness, the frequency of occurrence, the extent of the dampness, repair record, any complaints on the water seepage in identifying the source of such dampness. Visual Inspection and some testing tools like moisture mete can be applied in determining the source of seepage. In some cases, where we suspected the water seepage was caused by the defective waterproofing membrane from the upper unit or roof, a water ponding test may be adopted. At the same time, when we suspected the water dampness was raised by the leakage of the plumbing pipe, a meter test can be adopted in deterring the actual source of such seepage.

Photo showing a suspected case of water seepage

In order to maintain a safe and healthy environment for occupants, routine inspection, repair works, and maintenance works are suggested to carry out in every building.

Make Use of Verandah in High Rise Buildings for Fire Safety Aspect

The impact of Fire Safety Code in Hong Kong

The fire safety code has experienced a few rounds of reform. The most influential reform we opined was the code published in 1996 and also the code in 2011. While there are many honorable peers have shared the view to both code applicable in Hong Kong, GBE found one interesting HK-unique escape staircase arrangement which have been prevailing in 2 decades ago. This the verandah space intercepting between the apartment units and the requirement staircase (usually scissor-type)

 

Verandah Space being merged 

This verandah space was a space designed in half-open to the external air. The space is connecting between the staircase and the apartment unit through the fire-rated doors. Driven by congested space in Hong Kong, some verandah, in this case, has been enclosed by the window and merged to the apartment units. This was deemed to be against the fire safety code or approved plan.

 

GBP for showing the Typical location of the verandah in a domestic unit

The Provision of HK CAP 502

In 2007, the HONG KONG CAP 572 Fire Safety (Buildings) Ordinance has been put into enforcement. The “Purpose Of Ordinance” is cited in clause 2 of Cap 572 and We copied here as follows.

This ordinance is aimed to provide protection from the risk of fire of occupants, users, and visitors to certain kinds of composite buildings and domestic buildings.

The law further explains the requirements including fire service installation and equipment and fire safety construction for different kinds of buildings in its Schedule 1 , 2, and 3 correspondingly. The governing requirements stated clearly is to apply the Code 1996 as the “standard” to satisfy the intention of this Ordinance. Thus, the said “Verandah” enclosure or modification is likely in this radar.

 

What did Code in 1996 talk about the “Verandah”

In our view, there was no direct elaboration to the “veranda” being designed for the intercepting lobby between the required staircase and the unit. From the MOE code 1996 and FRC 1996, there was a few relevant paragraphs which came up eventually the “veranda” application as a protected lobby. Since the author was not the Code writer nor in an authoritative position to comment, this blog of write-up serves to trigger some interesting discussion.

 

The provision of the “Protection” lobby was written in clause 13.5 in MOE 1996 and the design of “Protection lobby” was explained in 11.3 FRC 1996. Nevertheless, the enclosing wall of the Protected lobby was further explained in clause 11.7. Honestly, it was a complex integration of different clauses at different code and could easily lead to various explanation outcomes. This undesirable situation such complex set of codes has been improved in lately 2011 code.

The interpretations of Protected Lobby stated in MOE 1996 Code

The design of “Required staircase and protected lobby” was explained in Clause 11.3 at FRC 1996 Code

The Clause 13.5 in MOE 1996 Code

Indeed, the old 1996 code has remarked very clearly in clause 13.5 MOE 1996 code that “such lobby shall be designed as a common area and an integral part of the staircase so that it could not be readily incorporated as part of any adjacent unit(s) of accommodation” The 1996 code did aware the issue of merging the protection lobby to the private unit. Nevertheless, the complex nature of the set of codes 1996 which led to different explanations may undermine the intention in clause 13.5.

Plan for demonstrating the Verandah between the required staircase and the apartment

Above is another example where the “Veranda” was inserted between the escape staircase and the apartment. Interestingly, the kitchen doors also opened to the verandah. It was believed that this layout configuration is hardly survivable in today’s Code.

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.

 

 

Fire Safety in Commercial Premises

Fire safety can be regarded as one of the primary considerations in building designs. The terms of fire safety cover a wide range of building concepts, ordinances, and regulations under the law. When we consider the fire safety works in banks, the concept of Fire Safety (Commercial Premises) Ordinance should not be omitted. The introduction of FS(CP)O is one of the ordinances which aims to provide better protection to the occupants and visitors on certain kinds of commercial premises.

Prescribed commercial premises and specified commercial buildings are under the scope of the ordinance.  For the captioned the premise, they are required to update that fire safety construction including means of escape, means of access, fire-resisting construction under the Code of Practice for the Provision of Means of Escape in Case of Fire 1996, Code of Practice for Fire Resisting Construction 1996, Code of Practice for the Provision of Means of Access for Firefighting and Rescue 1995 respectively. Also, the premises required to update fire services installation following Codes of Practice for Minimum Fire Service Installations and Equipment and Inspection, Testing, and Maintenance of Installations and Equipment 1994 when the total floor area exceeds 230 square meters.

As a building professional to cope with the above issue, a desktop study needs to be conducted first. It is essential to calculate the number/width of the exit door and exit route following the purposed usage of the premises. The comparison of the recorded plan and Fire Safety (Commercial Premises) Ordinance may draw attention to the fire safety deficiencies. The site visit is followed to identify the deficiencies. fire services system always associates with water supplies and electricity. For the aged building, some non-emergency services like electricity will be located in the exit route. However, those non-emergency services did not enclose by FRR materials. It may post a potential fire hazard. Insufficient width of the MOE route, insufficient number of exit routes to the required staircase, presence of the fire shutter in the exit route, absence of exit sign, absence of the exit door, etc are the common scenario for the aged commercial premises to deal with the ordinance. The reasons for the above deficiency can be caused by certain reasons including the change in use, the absence of the fire safety ordinance during the construction period, and unauthorized building works by the owners.

Boundaryless collaboration to turn state-of-art Architecture design into “down-to-earth” reality solution

In a highly congested urban context, how can a building stand out from the backdrop and become memorable ? There are strategies such as a practical internal layout, modern interior design and impressive building facade. Since buildings are usually arrayed in highly dense urban areas, the building facade becomes the first impression and first touch in many metropolitan cities. To create a distinct impression in international city likes Hong Kong, the architectural design created by powerful multi-cultural collaboration is the bespoke element underpinning the design solution.  

It is to the benefit of future users, landlords and every stake-holder of the development when the building is positioned and presented in the right site, right angle, right context and right location. To gear the architectural design toward practicality rich solutions, a down-to-earth technical analysis becomes profoundly important. K.P.D.O + GBE like many leading edge internationally award-accredited architects, believes a good balance of design, usage, layout, cost, and site features are essential to the development.

Grateful and thankful to collaborate, rather than presenting a simple yield diagram, K.P.D.O.+GBE. presented an aspirational solution showing the full site potential. K.P.D.O+GBE has analysed the details, negated technical deal breakers and prepared a sensible and approvable layout for the future user’s consideration. The turn-around for these are 6 days only. This assignment showcases and highlights our strong ability to find additional value whilst producing distinctive and memorable architecture.

 

Structural Appraisal to the Loading Case in Yuen Long Premise

When I was an undergraduate in Building Surveying, I learned from many textbooks that the structural design process usually starting with the loading assumption. This assumption is presented by outlining different loading cases. In simplicity terms, some loading cases are what we called UDL while some are point load.

Example of UDL

Example of point Load 

When we deepen the idea of loading further, there are generally three types of load including dead loads, live loads, and wind loads. Dead loads are due to the self-weight of the structure. Live loads consist of all the loads which are designated to be placed on the structure, For example, loads of people and furniture. This live load is strongly correlated to the usage and obviously the heavy-load machine will demand strong live load capacity.  Wind loads generally come from the pressure of wind acting on the structure.

Example of live load, dead load and wind load

In order to ensure safety and health for the built environment, Buildings Authority has enforced the Building (Construction) Regulations under HK CAP 123. There emphasizes the minimum imposed load or live load in our term for different usage. For instance, the distributed load for the domestic floor is designed as 2 kPa while the general restaurants are designed as 4 kPa. The structural design should follow this stipulated requirement to attain compliance.

 

Drifting down the river, the user of the structure, i.e. the occupier in the premises, may mis-sue or alternate the usage without carefully considering the designated live load. In our many Structural assessments.We noticed the occupier might have over-loaded the structure unintentionally or might have alternated the usage which exceeds the permissible live load.

 

In the situation like aforesaid said, the structural element itself may exhibit some undue behavior like the development of a huge crack on beam component or deformation. Adversely speaking, it is a very unfavorable observation because the structural damage may cause immutable damage to the elements. Sometimes, immediate propping or secondary support may be required to stop the damaging.