By Samson Tam Asset Enhancement • Building Technology 0 Comments

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.

By Mike Mak Uncategorized 0 Comments

Hand-free Toilet

In the week between May 7th and 15th, 867 COVID-19 infections were found in Thailand Simmummuang fruit and vegetable market. Health investigators in Thailand identified the entrance of the public toilet as the suspected source of most infections. This rises our concern on the infection possibility of public toilets in Hong Kong.

Simmummuang fruit and vegetable market: https://www.bastillepost.com/hongkong/article/8489819-%e6%b3%b0%e8%a1%97%e5%b8%82%e7%88%86867%e4%ba%ba%e6%96%b0%e5%86%a0%e7%a2%ba%e8%a8%ba-%e5%8e%9f%e5%85%87%e7%ab%9f%e6%98%af%e5%85%ac%e5%bb%81

Transmission Route in Public Toilets

According to Joseph Allen, associate professor at Harvard T.H. Chan School of Public Health, public toilets can be an important source of COVID-19 spread. The major way of spread are flushing and touching.

When toilet water contains viruses and bacteria, the churning and bubbling of water creates particles that will float in the air. These  viruses and bacteria will spread around the toilet, linger in the air and settle onto surfaces in the toilet. COVID-19 can survive in the air for 3 hours and even up to 24 hours in paper. Hence, the possible transmission route are people breathing in viruses when flushing and people touch installations in the toilets which viruses and bacteria settled.

COVID-19 in toilets: https://specialty.mims.com/topic/covid-19-in-hospitals–toilets–staff–public-areas-show-contamination-

Ways to Prevent Infection in Public Toilets

In Hong Kong, the most common way to prevent infection in public toilets are wearing mask, wash hands after using the toilet and increase disinfecting arrangements. Nonetheless, these precautions still remain some loopholes in our dense against COVID-19. One common example is after washing hands, people still need to hold the door handle and open the door. If there are some viruses settled on the door handle before, the people will also get in touch with the viruses and may get infected if he or she then touch his or her mouth, nose or eyes. This example is just a tip of an iceberg, in public toilets, not only we need to touch door handles, but also push button toilet flush, faucet handle, soap dispenser handle, etc.. The more we touch, the higher the possibility that we are infected.

Touching doors in toilets: https://health.ucdavis.edu/coronavirus/covid-19-information/coronavirus-mistakes.html

Touching Flush Button: https://www.pbs.org/newshour/health/public-bathrooms-carry-coronavirus-risks-heres-how-to-be-careful

To close up the loopholes, the best ways is to reduce the amount of viruses and bacteria spreading from flushing and minimize the need of touching in public toilets.

Reduce Viruses from Flushing

People no need to touch the toilet lid, the lid will automatically opens and closes when nearing or leaving the toilet. Therefore, even when people forget to close the toilet lid, the auto open/close lid will close the lid and reduce the amount of viruses and bacteria spreading.

Minimize the need for Touching

Although closing the toilet lid will reduce the amount of bacteria and viruses comes from flushing, there are still risk of getting infected in public toilets as it cannot minimize the amount of bacteria and viruses to 0. As a result, another effective precaution will be minimize the need for touching in public toilet, that is, to update a traditional toilet into a hand-free toilet. Here are the lists of installations in hand-free toilets.

  • Auto Toilet Door
  • Auto Flush Sensor
  • Auto Trash Bin
  • Auto Toilet Seat Sanitiser Dispenser
  • Auto Toilet Paper Dispenser
  • Auto Tissue Dispenser
  • Auto Soap Dispenser
  • Auto Faucet
  • Auto Door
  • Auto Hand Dryer

No ones knows when this pandemic will end, but we can try out best to minimize the possible spreading routes. Wearing mask and frequent disinfection are ways preventing viruses getting into our body, while upgrading toilets to hand-free toilets are smart ways to reduce the amount of bacteria exists in toilets. GBE will keep updating different measures to stop transmission route for the public to fight COVID-19.

GBE welcomes comments from professionals and enquiries from the Public

By John Lam Building Law • Building Technology • Design • Uncategorized • • • 0 Comments

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.