By John Lam Asset Enhancement • Building Technology • Design 0 Comments

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.

 

 

By Candy Yip Building Law • Building Technology • Design • Real Estate • 0 Comments

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.

By John Lam Asset Enhancement • Building Technology • Uncategorized • • 0 Comments

Part 1 : Coating materials for Aluminium cladding – Non-Combustibility

From natural anodisation technique to PVF2 coating technique , the aluminium finishing coating has undergone a lot of revolutionary advancement. In recent years, there came with the discussion about “Self-cleaning” of the aluminium coating surface. This is about the coating materials which gives effect to flush its’ surface every time in raining. “Self-cleaning” is indeed a merchants’ name . The behind sciences are varying from among different manufacturer.I have conducted some comparison among some cladding’s surfaces being applied to different “treatment” allegedly claim the self-cleaning properties.  In my small research , some coatings are sheet- applied on the surface of anodised aluminium cladding. Unfortunately, my research (limited online data searching) cannot conclude sheeting-applied one was made up compilable to the Section E clause 10.1 of FS code or as per the BS476 -part 4. Well, many peers have messed up the concept of BS476 – PART 6 / PART 7 which is about spread of fire to BS476 – part 4 which is non-combustibility .

 

There are some testing to confirm “non-combustibility”. The FS code of Hong Kong does a job to cite a reference table E1 to facilitate the conversion between BS and European standard . There are many building in Hong Kong are cladded with aluminium-panel externally , but the lack of attention is paid to its “non-combustibility” requirement. Example like “self-cleaning” sheet lining or coating or spray-paint applied materials and even the fire – ratardard which are applied on external architectural features. The add-on materials on top of the aluminium are sometimes commercially attractive in term of ease of application and its price but to the sacrifice of fire safety.

Fire accident in Grefell Tower, London

Photo : Wing On building in Sheung Wan was reported to have cladded with non-combustible cladding. Source from ejinsight on the pulse ( http://www.ejinsight.com)

In my next blog , I shall explain in details the “self-cleaning” being applied in aluminium cladding.

 

By John Lam Building Technology • Design 0 Comments

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.

 

By John Lam Asset Enhancement • Building Technology • Uncategorized • 0 Comments

“Loose of Neutral” in Electrical Circuit in traditional expensive residential apartment

The night scene of Hong Kong is always representing the prosperity and the stunning pictorial attraction for many people . The backdrop of the night scenery is the densely packed high-rise buildings being lit up.

With the air-conditioning became introduced in Hong Kong , some traditional luxury residential development was designed with 3 phases supply to cope with the loading consumption

Effect of Neutral Loss and Over-heat

The 3-phased live wiring is pairing with the neutral wire. The power runs into your apartment through “live” and return through “neutral . There is a defect called “nentral loose” which means the neutral wire loose contact or in bad connection. If there is “neutral loose” , that may be caused by various reasons, there will be abnormal arcing around the point of connection, a flash phenomena or spake fire will be occurred from time to time to heat up the already loose connection point and adversely causing unpredictable loading of electric current passing through the entire circuit. This circuit connects the load side appliance such as air-conditioners, the electronic parts or protection fuses of these electrical appliances may be damaged.

Inspection by Infra-red scanning and WR 2 checking

Unfortunately, it was not always detectable the abnormal heat up around the connection point . I prefer to adopt the infrared thermography scanning technique in my project or my inspection. However, the electrician today prefer to do by visual inspection which in my view may be subjective in some occasion. Our in-house infra-red is E4 model from FLIR. This is not the latest model, but still fit to our general routine checking.

 

 

 

By John Lam Asset Enhancement • Building Technology • Uncategorized 0 Comments

Acoustic performance in Curtain Wall

Curtain wall system is such a complex external envelope of the building . It is more than an enclosure but also to serve to reduce heat gain and sound proof. The evaluation of  heat gain is commonly considered by the amount thermal transfer in the energy unit. Nevertheless , lesser attention is given to the acoustic consideration . Thank to my friend Dr Man and our peers Lixil who shares me one table. The airborne acoustic reduction is considered by STC value which varies as per the glass panes composition and thickness of glass. STC is to measure the degree of decibel reduction. The reduction is further related to the hertz of sound transmission. For easy communication , each composition of glass panes will be assigned the STC value. The interesting observation is that the “laminated glass” is achieving similar STC value compared to similar glass panes thickness of “insulating glass unit”. Furthermore , A 12mm thick single panes can achieve similar STC value to 6+12+6 insulating glass unit. Indeed, there are more consideration to the curtain wall acoustic including the impact-borne sound transmission caused by impact to the mullion or transom . Sometimes, the provision of the noise barrier or the provision of the balcony projecting out from the external facade can help to reflect the unwanted sound such as traffic away.

 

By John Lam Asset Enhancement • Building Technology • • • 0 Comments

Protect your roofing membrane

When I was a boy, I saw the construction worker at roof heating up the Asphalt block with very bad odour smell. Bituminous asphalt were usually applied in liquid form in row by row with some over-lapping at even interval spacing. Although this materials are proven to be very weather resistance and durable once after curing and set, it is not encouraged to use in new works as per the General Specification (ASD) Clause 12.50. With the advancement of technology , there are now coming with various type of ready-applied roofing felt and some type are even in spraying form.

Nevertheless, the typical defects like blistering of membrane, sagging of membrane, incorrect surface water fall , poor outlet details , lack of backing rod for sealant in expansion, add-on structure impairing the roofing are still prevailing. These are attributed to the poor workmanship, lack of inspection and inadequate design details consideration. Indeed, even though the defects exists , it does not mean we have to end the life of roofing by complete re-roofing. A more sensible way is to carry regular inspection and maintenance than to leave the roof undue long time unattended.

 

By John Lam Asset Enhancement • Building Law • Building Technology • Uncategorized • • 0 Comments

Coring the rock stratum engineering our pile foundation

Site investigation is a term to cover a lot of aspect about the site. For the Engineer in construction site, it means the process to find out the soil and rock condition. From the project management perspective, we see the most essence is whether the quality control system is working well in place . This control system involves sampling , inspection, recording and counter-check. Although the PNAP has imposed a lot of restrains in the site investigation, the entire controlling mechanism still heavily rely on the professional site staff. The sample taken will be inspected the the engineer. This inspection is to be fed back to the Designer to confirm the design assumption of piling coincide well to what happens on site. This is the feedback loop essentially important in the entire QA process.

I witness the coring process and I can say the coring of soil / rock is not a pleasant job. Sometimes, the sample was damaged in the process, sometimes, the sample was dropped in pieces. Thus , a good sampling and coring process did demand patience by labour, right machine set up, on-site engineer inspection and recording.

 

 

By John Lam Building Technology • 0 Comments

Surveying technique to the structural opening found in the RC beam

Professional Building Surveyors are always called on board to do structural survey. There is one situation where the RC beam is cored with the opening and this caused a lot of anxious to the occupier about its structural safety. Usually , the surveying to this kind of damaged structural elements are tricky and professional. It needs to review the original structural frame ; RC beam rebar details , slab thickness and the exact position of opening being formed on the beam section

Details of infrastructure – Construction worker hands securing steel bars with wire rod for reinforcement of concrete

Since the reinforced concrete beam is composed of the rebars configured in designated position to achieve different structural purpose, thus , the inspection to the opening . To ensure a complete and proper visual inspection to the rebar is in place , we adopt the endoscope to inspect also the inside view of the opening . It is to technically identify whether any rebar has been damaged. Also , it helps to ensure the opening was not backfilled with undesirable materials.


Once the visual inspection is done and recorded , we need to cross check with the original design and identify the fall-short and assess the physical damage. Sometimes, we need the input from Structural Design to advise the structural loading capacity effect from the physical damage

Since the portal frame can be either fixed joint or pin joint in nature , thus the beam may exhibit different bending moment . The opening formed on the beam may diminish much the bending moment capacity of beam if the opening were wrongly poised and erred sized

By John Lam Building Technology • 0 Comments

Maintenance Problem from “Party Wall” in Urban area

According to the Land Surveyor “Word Press” 16, Aug 2012 “by Edmond Cheung,  “Party wall” is the physical separating wall of two adjoining building. It functions to divides houses of two different owners buildings but the wall is in shared ownership. In the DEVB(PL-CR) 2/15-08 dated 29th Mar 2010,

A party wall is an integral element, and it is unlikely that half of the same can be removed with the other half remaining intact. Therefore, the removal of the party wall is subject to heavy control stated in Buildings Ordinance Cap 123. To the very least, the lot looking for removal of his own part of “party wall” must have the consent from the rest of owners of the “party wall”. To ensure the integrity of remaining half , we usually apply the structural strengthening by in the steel bracing bolted and mounted to the structural element of the building.

This remains of party wall structure , i.e usually the half of its original wall, becomes some maintenance issues attributed to the already aged cement mortar in brick and rusting of the steel bracing by weather. The steel members sometimes become rusty and decomposed to have lost its strength and also becomes bittle . This also creates the problem of water seepage through the bolt hole path to the interior space. Owners also need to aware that the thickness of party wall is GFA consumable. Since the problem of maintenance is impairing much the integrity of wall and also poses the water seepage problem , it is important to pay attention to it maintenance and to carry out routine inspection.

The steel bracing is bolted to the structural frame of the RC building and this bracing to strengthen the integrity of the “party wall”