Help Your Planet

by John Herbert

Kids are far smarter than we given them credit. Possibly the best gift for your children is a Kelcroft audit, and help save the eco system problems. That is a story you can tell to your kids!

Unhealthy Hong Kong Homes

by John Herbert

We spend many hours indoors every day, and during the covid19 pandemic many people are forced to work from home.

If you or your family are suffering from persistent illness, symptoms might include headaches, fatigue, allergy, asthma, diarrhoea, or flu like symptoms, your home could be unhealthy causing sickness. Kids are still growing, and can be particularly susceptible to different types of illness during their development.

If you want to discuss your unhealthy building, call John Herbert 2335 9830 today!

Damp, pollution, faulty drains, faulty ventilation, and water seepage are just of some of the reasons causing an unhealthy home, persistent illness in your family indicates you could have a problem. Do you regularly see your neighbour in the local GP’s surgery or in the hospital, that could indicate both families are living in a sick, unhealthy building.

In Hong Kong, medical professionals are reporting that patients appear to be ignoring symptoms and illness, and do not seek medical attention early enough! Don’t delay already seek doctors advice immediately.

#sickbuilding #sickbuildingsyndrome #unhealthy

Missing Vent Pipe Plumbing and Drainage 101

Richland Gardens, Block 6, Kowloon Bay, Hong Kong COVID19 cluster

Realise, in high rise buildings suction pressure inside the drainage stack will continuously pull the traps (that means suck the water of the U traps leaving an empty and open U trap) if no vent pipe is provided, and creating COVID19 path into your home. The vent pipe is designed to prevent suction pressure (negative pressure) inside the drainage stack.

Filling each U trap once a week is not going to help if the stack in your building does not have a vent pipe (sometimes called balanced pipe) to relieve the pressure and prevent suction pulling the traps.

You don’t know what you don’t know, so go ask somebody who does :)

#drainage #design #Utrap #hongkong #drytrap

covid in the same tower block

by John Herbert

Tower block at Richland Gardens Estate ,Kowloon Bay,Hong Kong 13-12-2020
COVID Vertical spread at Richland Gardens Estate, Block 6, Kowloon Bay,

UPDATE: 14 December 2020

different building – new vertical cluster

A residential building called Kwai Tung House in the Tung Tau Estate, Nga Tsin Wai is reported to have nine cases in six different units, where most of the patients come from flat number 15 (on different floors). CHP said maybe a structural problem (meaning drainage system) Dr Yuen will investigate.

UPDATE 11 December 2020

Environmental samples were taken from Block 6 apartments, COVID19 positive results were discovered on the piping, floor drains, and exhaust fans

Logically, it appears that COVID19 entered through the floor drain trap into the space (bathroom?) exposing the residents to the COVID19 virus.

The positive results discovered on the exhaust fans is a new development. Perhaps the exhaust fan handling contaminated air with suspended droplets itself becomes contaminated, and potentially discharges contaminated air. And when the extract fan is switched off, its a contaminated surface, risking touch/contact transmission. Safety precautions are needed for handling and cleaning exhaust fans.

RTHK has now issued a news report with video (ENGLISH):

Dr Chuang Shuk-kwan (11-12-2020) mentioned in passing that earlier investigations also found COVID19 in the fan system, although I don’t recall any announcement.

#exhaustfan #ventilation #HVAC

10 December 2020

Richland Gardens is a residential housing estate located in Kowloon Bay, Hong Kong comprising 22 high rise tower blocks, a small outdoor public transport interchange, and a medium sized shopping centre.

RTHK and SCMP have reported seven covid19 cases so far, located on different floors of the same tower, all in Block 6, and all residing in flat D. In addition, one case was reported in Block 4, and one case in Block 18.

CHP requires all residents in Richland Gardens Block 6, all floors, flat D, and Block 18, all floors , Flat E, must be tested, to me that indicates potentially more cases in Block 18 will emerge in the next few days.

After the horse has bolted, experts turned up to visit the Block 6 with microbiologist Dr Yuen, after the inspection Dr Yuen stated the drainage could be the source, because all the cases were in flat D, on different floors, but not every U trap could be seen (no access?)

RTHK managed to interview several Block 6 residents, who stated that the Block 6 drainage system was leaking!

Strange that BD, EPD or Dr Yuen didn’t mention leakage that in their post-inspection press conference. Dr Yuen did suggest pointed out that all residents in Block 6 should be quarantined, but the quarantine accommodation is already full, another no room at the inn story ✨✨✨

From bitter experience (e.g. SARS 2003) and other buildings, we know that sub-standard drainage systems can spread disease in the same high rise building, for Richland Gardens the early evidence tends to indicate that the cause is probably the poorly maintained drainage system (again). Has nobody heard that Prevention is better than the cure!

As shown in previously posted photos, it is easy to find located drainage systems that have not been properly maintained, but we have to wait for the next batch of people to be hospitalised before BD, EPD and HA pay a site visit.

Fingers crossed this cluster does not expand across the other 22 tower blocks in the estate.

#drainage #sewerage #conditionsurvey #buildings #kowloonbay #plumbing #buildingmanagement #plumbinginstallation #floordrains

Building Air Leakage Resource Centre

by John Herbert (@johnherbert)

For building owners building air leakage costs extra money, whether it is through the additional energy use or poor indoor environmental quality. The latter, infiltration of polluted outdoor air and Radon are both a serious health concern impacting occupants.

Attempting rectification after occupation/renovation is always more difficult and time consuming, so the execution of the construction work is vital, we know it has a major impact on the airtightness of buildings.

Air leakage can be tested and verified during construction, using a 2 stage process using blower door test, supported with thermography (Infrared) and fog testing, to ensure unwanted air leakage is minimised.

In 2004 HK BEAM created 4/04 green building rating tool for new buildings, that introduced air leakage testing, and later in 2012 BEAM PLUS Interiors rating tool introduced air leakage testing for shops and offices, but regulation has not followed. Europe now has strict regulations requiring new buildings to undergo air leakage testing, to meet the country standard.

John Herbert organised air leakage seminar in 2015

Therefore to help reduce building energy use and wasting energy, air leakage standards and testing are needed here in Asia.

Air Leakage Frequently Asked Questions (FAQ)

What is Building Air Leakage?

A building envelope with openings, sometimes due to poor construction, allows polluted outdoor air into the building.

What are the consequences of air leakage in buildings?

In Asia, air infiltration has several consequences:

  1. allowing hot humid air to enter an air conditioned building, causes condensation on interior surfaces, providing the right environment for growth of mould inside buildings;
  2. poor indoor air quality impacts the health of occupants;
  3. increased energy use;

How to Identify Building Air Leakage?

Air leakage can be detected using blow door test, thermography, fog testing to identify the location of the air leakages, but in most cases these do not quantify the amount of leakage corresponding to each leakage.

What is the Key Issue for Buildings with Curtain Walls

According to the ASTM standard for curtain wall construction, curtain wall have permitted air leakage rate that qualifies for the ASTM standard. ( xxx litres/sec at 300pa). that means buildings with curtains walls have air leakage.

Resources (suggest a resource?)

Retrotec blower door Online Training

German Air Leakage Association Handbook (Chinese)

German Air Leakage Association Handbook 2 (Chinese)

Building Air tightness article by John Herbert (HK)

Air Change in Low and High-Rise Apartments research (HK)

A Guide on Indoor Air Quality Certification Scheme for Offices and Public Places 2019 (HK)


Passive Haus Guide (UK)

Analysis of Large Building Air Leakage
Testing DOD (USA)

Air Testing Standard Military (USA)

ATTMA Air Testing Standard 1 (UK)

ATTMA Air Testing Standard L2 non-domestic (UK)

BEAM Plus – Interiors rating tool (PDF)

HK BEAM 4/04 version (PDF page 1-20)


tightness EU newsletter (PDF) Nov. 2020


  1. CAN/CGSB 149.15 – Determination of the Overall Envelope Airtightness of Buildings by the Fan Pressurization Method Using the Building’s Air Handling Systems
  2. The United States Army Corps of Engineers Air Leakage Test Protocol for Building Envelopes
  3. ISO 9972:2006 – Thermal performance of buildings — Determination of air permeability of buildings — Fan pressurization method
  4. ASTM E779 – Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
  5. ASTM E1827 – Standard Test Methods for Determining Airtightness of Buildings Using an Orifice Blower Door
  6. EN 16798-3: 2017: “Energy performance of buildings – Ventilation for buildings – Part 3

tags: air leakage, infiltration, exfiltration, permeance, building envelopes, airtightness

BEAM PLUS, HVACR Air filters, and COVID

While it seems everyone is scrambling to retrofit their HVACR systems with air filters rated at ASHRAE MERV13 to mitigate the impact of COVID-19 virus. However, the smart building owners that followed the BEAM PLUS v1.2 NB IEQ5 credit requirement already have MERV15 air filters installed!

That BEAM PLUS standard was set years ago in 2010, and it is still better than MERV13 benchmark specified by WELL 2016 version.


Lousy IAQ Analysis

Restaurants in Hong Kong must comply with the relevant provision of the FEHD licensing requirements. For Air-conditioned restaurants, typically the indoor air is largely recirculated with a small quantity of fresh air / outdoor air added into recirculating air steam.

By law, the minimum requirement is provided in clause 42 of the licensing requirements, only 17m3/hr/person (or 4.2 litres/sec/person) [1] of fresh air / outdoor is required, to put that into perspective that rate is lower than the normal 7-10 litres/sec/person rate.

Of course, the result is poor IAQ quality, because the air pollutants, including airborne covid19 [2] concentrations, are diluted extremely slowly.

“Poor ventilation may play a major role in transmission” RTHK reported the spread of covid19 investigation [3]. However, as explained above, it is no surprise, all Hong Kong restaurants have little fresh air/outdoor air, thus are poorly ventilated, and any bacteria/virus in the air is not diluted.


Don’t Do Stupid Things

The above drawing is from a new air conditioning building (designed 2020), an interior vapour barrier is stupid!

Why? The external vapour pressure is significantly higher (approx. 1kpa higher) than the interior vapour pressure in the air conditioning space, causing moisture flows toward and into the room.

However, the internal vapour barrier stops the flow, and traps moisture saturating the thermal insulation with water and destroying its thermal properties, and increasing the building energy consumption.

HKGBC recent asked for ideas to promote nett zero and lower energy consumption, the first step I suggest must be stopping architects doing stupid things!


Tips to avoid Hong Kong Tenant Complaints About Mould

Instead of handling mould after it occurs let’s try a different approach.

When a property suffers from damp and mould, the tenant suffers, but also the landlord, committing extra time and energy for handling the issue, so here are some tips for landlords to avoid mould <<<< click here

Building Infrared Inspection

Building infrared inspection reveals hidden defects not visible to the human eye, the temperature image can locate the source of water ingress, damp, water damage, locate missing sections of thermal insulation missing, identify overheating switchgear, and much more.

#hongkong #thermography #infrared #building #inspection #condition survey

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