By samsontam@me.com Asset Enhancement 0 Comments

Condensation Issue in Building – Part 1

Unwanted condensation can cause the building damage and also affect human health. In Hong Kong, condensation is a common problem which almost every single owner has to deal with. Temperature difference and high humidity are the main causes lead to condensation occurs.

Condensation is created when warm moist air begins to cool down and the moisture is released. This moisture then settles on cold surfaces making them damp. This can happen quickly when warm moisture in the air connects with cold air or surfaces, such as having a shower and the steam from the shower hits the cold window or mirror making it wet to touch, this is condensation.

Source: https://www.falkirk.gov.uk/services/homes-property/council-housing/repairs-maintenance/docs/condensation/Condensation%20in%20your%20home.pdf?v=201910291603#:~:text=Condensation%20is%20created%20when%20warm,and%20the%20moisture%20is%20released.&text=This%20can%20happen%20quickly%20when,to%20touch%2C%20this%20is%20condensation.

Information from Hong Kong Observatory

March and April are milder although there are occasional spells of high humidity. Fog and drizzle can be particularly troublesome on high ground which is exposed to the southeast, and air traffic and ferry services are occasionally disrupted because of reduced visibility. May to August are hot and humid with occasional showers and thunderstorms, particularly during the mornings. Afternoon temperatures often exceed 31 Degree C whereas at night, temperatures generally remain around 26 Degree C with high humidity. There is usually a fine dry spell in July which may possibly last for one to two weeks, or for even longer in some years.

Source: https://www.hko.gov.hk/en/cis/climahk.htm

 

On average, May is the most humid.

On average, December is the least humid month.

The average annual percentage of humidity is: 77.0%

Source: https://weather-and-climate.com/average-monthly-Humidity-perc,Hong-Kong,Hong-Kong

Due to such high temperature and high humidity environment in Hong Kong, condensation will be easily occurs if lack of consideration in daily operation and usage of room. GBE has deal with many condensation cases caused by lack of communication in design stage and also in wrong material selection. With an detailed study and planning before design stage which can help in material selection and insulation. Also, the heat source from outside the unit or building will be needed to consider through out the design process.

Negative pressure in building which may cause a big effect of condensation as the hot air from outside collide with the cold air within the building. Many people deal with condensation problem with balancing the temperature and humidity difference between indoor air with outdoor air by ventilation. However, such measure is not practical when outside air is in high humidity which the ventilation system is not sufficient for get away the moisture within the area as the high humidity air will get through the window to indoor by negative pressure.

Source: https://basc.pnnl.gov/sites/default/files/images/HVAC515_whlbldgvent4_DS_1-10-13.jpg

The above image show that the exhaust-only ventilation only system may cause negative pressure which can easily made the outdoor air to the building or unit. In below example, a cold storage with 24 hours A/C control store room which was found with condensation problem with hot air getting through from outdoor air by negative pressure. The owner has installed a few dehumidifiers which were not sufficient to get rid of the moisture as the hot air from outdoor is non-stoppable. In such case, the high cost in electricity usage and also high maintenance cost may affect the owner in daily operation. GBE has studied and apply the insulation to stop the hot air to get in from the electrical cable duct and also can save the cost for running the dehumidifiers and prevent the rusting effect at the electrical cable duct. 

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 Candy Yip Building Law • Design • • • • 0 Comments

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.

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 Ricky Chau Building Law 0 Comments

Expert Witness (Construction)

Acting as the “Expert witness” to offer expert opinions to the court is a very meaningful assignment for the building professionals. Nevertheless, the Expert should act impartially to provide his expertise and experience to the matter or direction given by the court.

Sometimes, the court discredits the weighting of expert witness opinion because the expert may cherry-pick on providing the expert analysis on the matters concerned.

”In Dr Chan’s report, he appended a number of “assessment” and “condition survey” reports (Reports) prepared by Wong & Cheng Consulting Engineers Limited (WC) for the Owners prior to the 2015 Order. The assessment/survey reports attached to an expert report were inadmissible on the basis that although leave had been given to adduce the expert report, it had not been given to adduce the assessment/survey reports attached to it. The Court pointed out that expert evidence is not only evidence of opinion, but also factual evidence which goes to an expert issue. ” (Expert reports within expert reports and the need for leave to adduce them – Deacon, 2019)

It is undeniable that the factual evidence and dispute could become the admissible opinion but not only the jargon words. As seasoned experts in the construction field, we adhere to the Code of Practices (COP) and construction standards, therefore we can provide reliable professional advice and expert witness testimony.

Dedicating to the construction assignment of “Expert witness” can showcase our superior knowledge and skill in the construction industry, and can also tackle the deadlock situation and bring to light in court.

Paramount importance is to assist the parties in approaching the fact of matters and hopefully the contesting parties can settle the disputes eventually.

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.