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Guide to the Management of Indoor Air Quality for Hotels in Hong Kong

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Forward…

Hotel buildings… A hotel building is many things; a place of work, a homeaway from home, a place of recreation and entertainment,etc. Internal spaces include basement work areas,corridors, restaurants, kitchens, guestrooms, meetingrooms, ballrooms, etc. Hotel guests and employees spenda substantial amount of their time inside the hotel.Guests may occupy these for relatively long periods, suchas their rooms, or for very short periods, such as lobbiesand corridors. Employee work shifts may cover manyparts of the back-of-the-house areas, on confined to onearea for periods of up to twelve hours.

Indoor environments…

The indoor environment may be characterised by thermalcomfort (temperature and relative humidity), lighting,noise and vibration, and indoor air quality (freshness andabsence of pollutants).

Indoorenvironmentalquality…

The quality of the indoor environment has an impact onguest comfort, and their perception of quality, and onworker productivity. Poor indoor environments detractfrom caring image and quality of the lodgings.

Buildingperformance…

An efficient hotel building is one in which the ‘services’provided to guests are maintained at a level of qualityappropriate the standard of the hotel, whilst at the sametime the resources consumed are minimised.


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Indoor air quality… In terms of indoor air quality, it would not be goodmanagement practice to try and save resources if theindoor air quality suffers as a consequence. Good IAQdepends on an adequate supply of fresh air, absence ofpolluting sources, and good distribution to the breathingzone of the occupied spaces.

Perceptions of poorair quality…

Other environmental factors, such as thermal comfort,noise and lighting may give occupants a sense that indoorair quality is poor. Even the best designed air-conditioning and ventilation system targets at providingthermal comfort conditions which satisfy around 80% ofoccupants, so a large percentage may be dissatisfied evenwhen optimum conditions (for the majority) exist.

Impacts of poorindoorenvironments…

The impacts of a poor indoor environment may beregarded at three levels:

• discomfort, such as being too cold, suffering fromlighting glare, noise, objectionable odours, etc;

• health impacts such as nasal irritations, eyeirritations, colds, etc., which may lead toabsenteeism; and

• health risks, such as from radon, legionella bacteria,asbestos.

The key message for management is not to ignorethe issue, not to be afraid of dealing withproblems, rather to be positive about managingthe situation!

This Guide… This Guide is based on the extensive experience of theauthors and their colleagues in dealing with IAQproblems in buildings in Hong Kong. Many consultantscan undertake surveys and measurements of air quality.This Guide seeks to enable hotel managers to understandthe key issues, to appreciate how and where problemscan arise, and to understand how to deal with thesituation in their hotel. In many cases problems withrespect to indoor air quality are isolated to a few areas, orare not severe enough to effect health.

Authors… Dr. Daniel W T ChanProf. John Burnett

With assistance from Horace Mui, Thomas Tung, JulianChan. Front cover graphics by Dominic Leung.


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Efficiency…

Use your senses!

Walkthrough surveys can tell you from sights and smells if there are obviousproblems.

The first level of action is to remove the obvious problems. Water, stains, persistentcomplaints, etc, will point towards obvious problem areas.

Second, do some basic measurements to establish the seriousness of the situation,e.g. measurements of CO2 to indicate lack of fresh air.

If problems persist, investigate further with the aid of an engineer familiar with themeasurement protocols, engineering system design, materials use, etc.

Measurement of pollutants is necessary in some situations, but thesophistication of the measurement protocol depends on the level ofperceived annoyance, discomfort or health risk. It is generally acceptable tofind out if the level for a single pollutant is below the air quality objective,rather than to measure the level with precision.


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Managing Indoor Air Quality in Hotels…

Governmentinitiatives…

The Indoor Air Quality Management Group of theGovernment of the Hong Kong Special AdministrativeRegion released the second draft of it’s Guidance Notesand a Consultation Paper for the Management of IndoorAir Quality in Offices and Public Places in October 1999.These documents specify the objectives of indoor airquality (IAQ) deemed to be achieved in public buildings.Although this requirement is voluntarily, it is theintention of the EPD to regulate acceptable IAQ followinga review of the extent of voluntary compliance.

There is likely to besocial pressure forquality hotels to meetthe highest levelcriterion!

The management of indoor air quality in hotels should betaken seriously for two strategic reasons:

• Firstly, there is no reason why hotels can beexempted from regulatory control of the IAQ.

• Secondly, quality buildings are likely to expected tomeet the most stringent Level 1 requirements of theGuidance Notes through a certification procedureadministered by EPD.

Should Hong Kong adopt criteria for the responsibility forhealth and safety similar to those of other developedcountries, hotel management will come under greaterpressure to act positively. Under the UK’s Health andSafety at Work Act 1974, it is the employer “to ensure, sofar as is reasonably practicable, the health, safety andwelfare at work of all his employee”. Also, “to ensure, sofar as is reasonably practicable, that persons not in hisemployment who may be affected thereby are not exposedto risks to their health or safety.” Under the same act, anemployee (or building occupant) can held liable unless he“takes reasonable care for the health and safety of himselfand of other persons who may be affected by his acts oromissions at work.” Education of both the employers andemployees are equally important.

Ailments arising from adverse IAQ are difficult to identify. However, HongKong had its first case in 1998 when a former musician in the Hong KongPhilharmonic Orchestra was awarded HK$20 million for brain damagescaused by over exposure to pesticide in indoor air during rehearsals. The fivedefendants were found guilty in the Supreme Court and were held liable forthe legal fee of HK$200 million!


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The ‘Sick BuildingSyndrome’…

The oil embargo in 1973 triggered an energy crisis.Designers were under pressure to conserve energy in allbuilding services systems. Engineers at that time madethe mistake of cutting too many corners. Recommendedfresh air quantities were reduced, indoor air temperaturesset higher in summer and lower in winter, lighting levelswere reduced, etc. This resulted in a large number ofcomplaints and ailments reported in air-conditionedindoor spaces. The ailments were mostly respiratory andneurological disorders without serious physicalconsequences. These ailments were collectively describedas ‘Sick Building Syndrome (SBS)’ by the World HealthOrganization early in 1980.

Unacceptable IEQ… While SBS can be a complicated issue, many of thecauses are related to unacceptable indoor environmentalquality (IEQ). IEQ can generally be described by the fourindoor environmental qualifiers, that is:

• indoor air quality comfort;

• thermal comfort;

• visual comfort; and

• aural comfort.

Indoor air quality distinguishes itself from the other threequalifiers for the following reasons:

• causal factors are numerous and cross disciplinary;

• substances found potentially harmful to healthindoors are numbered in thousands and sometimesinvisible when that substance is colourless andodourless (e.g. carbon monoxide, radon);

• poor IAQ not only affects comfort and health, it canmaim or even kill in extreme cases;

• generally difficult to qualify and much more difficultto quantify; and

• there are precedence of legal liability.

Figure 1 shows that IAQ stands out with high percentageof dissatisfaction. However, in the current practice inbuilding services system design, over 90% of the initialand running cost is spent on keeping the space thermallyacceptable. In any energy conservation programme, freshair quantity is often the first item which is cut back.

As the general public becomes better educated onimportance of good air quality inside premises,good air quality will be a selling point in the newmillennium.


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IEQ Qualifiers… Survey by BSE Department, Hong Kong Polytechnic University (1992-1994)

0

5

10

15

20

25

30

35

40

IAQ Thermal Viual Aural

IEQ Qualifiers

Per

cen

tag

e o

f D

issa

tisf

acti

on

Figure 1. Typical Distribution of Percentage ofDissatisfaction of the Four Fundamental IEQ Qualifiers,

Survey done on 17 offices.

Indoor air qualityobjectives…

Today, there are numerous amounts of information onIAQ - standards, codes of practice and research data -describing and discussing problems and solutionsrelating to IAQ. If there are still problems with IAQ, it isnot because there is no solution. IAQ problems persistdue to the lack of clarity about the control criteria. Takinginto account the complicated factors depicted in Section2, there is so far no widely accepted IAQ criteria that canturn into an IAQ standard. Instead, we work with IAQObjectives. The following sections are dedicated to aproviding a better understanding of the method forachieving acceptable IAQ.

Definition foracceptable indoor airquality…

Acceptable Indoor Air Quality (IAQ) is defined byAmerican Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE 62-1999) as:

“Air in which there are no known contaminants at harmfulconcentrations as determined by cognisant authorities andwith which a substantial majority (80% or more) of thepeople exposed do not express dissatisfaction.”

It is clear that the perception of acceptable IAQ embracesboth the health and comfort concerns.


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Other definitions related to acceptable IAQ are:

• The World Health Organisation (WHO)recommended for non-industrial indoor environment,“Unwanted odorous compounds should not bepresent in concentrations exceeding the ED50

detection threshold. Similarly, sensory irritantsshould not be present in excess of their ED10

detection threshold” [The ED50 stands for the 50th

percentile Effect Dose] (cited from EPD GN).

• The WHO defined health as “A state of completephysical, mental and social well-being and not merelythe absence of disease or infirmity” (cited from EPDGN).

• Building Related Illness (BRI) refers to bodilyailments induced by a known causative factors andthe effect is usually obvious. It can be acute orchronic. Its characteristics are:

• contraction of disease or obvious damage to humanbody or body parts;

• causative agents are identifiable as poisonous orpathogenic;

• causative agents are generated, circulated andexemplified in nursery beds existing in the building orbuilding services systems;

• illness takes longer to recover from and is very oftenfatal if due care is not exercised on time;

Examples of BRI are (Godish 1995):

• nosocomial infections;

• hypersensitivity diseases (such as hypersensitivitypneumonitis, humidifier fever, asthma, allergicrhinitis);

• legionnaires’ disease;

• fibreglass dermatitis;

• direct toxic effects from exposures to contaminantssuch as carbon monoxide, ammonia, formaldehyde,pathogenic micro-organisms and etc.

Sick Building Syndrome (SBS) occurring in an indoorspace has various names used by different researches.Among them are:

• Building sickness

• Sick office syndrome

• Tight building syndrome

• Office eye syndrome

• High building syndrome


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• Monday syndrome

• Long weekend syndrome.

It is the term ‘sick building syndrome’ used by WHO(1982) that is the most prevalent.

The term SBS in itselfis a misnomer

A rather vague definition by ASHRAE; “If morethan 20% of the occupants in a buildingcomplain about one or more sickness symptoms;if these symptoms persist for more than twoweeks; if the cause of the complaints is notreadily recognisable; and if those personsaffected recover from such symptoms on leavingthe building, SBS is said to occur”.

IAQ health objective… The HKEPD recommends an IAQ objectives for OfficeBuildings and Public Places in Hong Kong that the hotelmanagement can take as reference (Table 1). HKEPDfurther recommends an IAQ objectives for individualvolatile organic compounds (VoCs) for reference purpose(Table 2). The goal is to maintain IAQ at a level suitablefor the building type, usage and the user group to sustaina healthy indoor environment.


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Table 1. Recommended Indoor Air Quality Objectives for Office Buildings and PublicPlaces in Hong Kong (Table 3-1 of the HKEPD Guidance Note).

8-hr average (at 25oC, 101.3 kPa)Parameters Unit

Level 1 Level 2 Level 3

Carbon Dioxide (CO2) ppm <800 <1,000 <5,000

Carbon Monoxide (CO) µg/m3 <2,000 <10,000 <29,000

Respirable Suspended Particulates (RSP) µg/m3 <20 <180 ---

Nitrogen Dioxide (NO2) µg/m3 <40 <150 <5,600

Ozone (O3) µg/m3 <50 <120 <200

Formaldehyde (HCHO) µg/m3 <30 <100 <370

Total Volatile Organic Compound (TVOC) µg/m3 <200 <600 ---

Radon (Rn) Bq/m3 <150 <200 ---

Ariborn Bacteria cfu/m3

500 <1,000 ---

Room Temperature oC 20 – 25.5 <25.5 ---

Relative Humidity % 40 – 70 <70 ---

Air Movement m/s <0.2 <0.3 ---

Table 2. Indoor Air Quality Objectives for Individual VOCs (for reference purpose only,from Table 3-3 of the HKEPD Guidance Note)

Compound Levels 1 & 2 Level 3 OdourThreshold

IARC*Classificati

on

Benzene 0.005 ppm(16.1 µg/m3)

0.5 ppm(1,600 µg/m3)

12 ppm(39,000 µg/m3)

1

Formaldehyde 0.025, 0.081 ppm(30, 100 µg/m3)

0.3 ppm(370 µg/m3)

0.83 ppm(1,040 µg/m3)

2A

Carbontetrachloride

0.016 ppm(103 µg/m3)

5ppm(31,000 µg/m3)

96 ppm(613,000 µg/m3)

2B

Trichloroethylene 0.143 ppm(770 µg/m3)

50 ppm(269,000 µg/m3)

28 ppm(153,000 µg/m3)

2A

Tetrachloroethylene 0.037 ppm(250 µg/m3)

25 ppm(150,000 µg/m3)

27 ppm(186,000 µg/m3)

2A

Chloroform 0.033 ppm(163 µg/m3)

10 ppm(60,000 µg/m3)

85 ppm(422,000 µg/m3)

2B

1,2(1,3)-Dichlorobenzene

0.083 ppm(500 µg/m3)

25 ppm(150,000 µg/m3)

0.30 ppm(1,830 µg/m3)

InadequateData

1,4-Dichlorobenzene

0.033 ppm(200 µg/m3)

10 ppm(60,000 µg/m3)

0.18 ppm(1,100 µg/m3)

InadequateData

Ethylbenzene 0.338 ppm(µg/m3)

100 ppm(434,000 µg/m3)

2.3 ppm(10,000 µg/m3)

Not Classified

Toluene 0.29 ppm(1,092 µg/m3)

50 ppm(188,000 µg/m3)

2.9 ppm(11,110 µg/m3)

3

Xylene 0.338 ppm(1,447 µg/m3)

100 ppm(434,000 µg/m3)

1.1 ppm(48,500 µg/m3)

3

*International Agency for Research on Cancer (IARC) Classifications:Group 1: The agent is carcinogenic to human (sufficient evidence of carcinogenicity in humans).Group 2A: The agent is probably carcinogenic to humans (limited evidence of carcinogenicity in humans andsufficient evidence in experimental animals).Group 2B: The agent is possibly carcinogenic to humans (inadequate evidence of carcinogenicity in humansbut sufficient evidence in animals).Group 3: The agent cannot be classified as to its carcinogenicity to humans.Group 4: The agent is probably not carcinogenic to humans (evidence suggesting a lack of carcinogenicity inanimals).


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IAQ objectives… The 3-level IAQ objectives is established to act as thebenchmark for evaluating and assessing IAQ with thefollowing intention:

Level 1This represents very good IAQ that a high-classbuilding should achieve.

Level 2This represents IAQ that provides protection tothe public at large including the very young andthe aged.

Level 3This represents IAQ that is required to protectworkers and employees as enforced under thecurrent occupational safety and health laws.

Level 3 is inherited from the requirement of the LabourDepartment (1998) based on occupational exposure limits(OEL) for chemical substances in the work environment.

According to EPD “If all the parameters for ‘Levels 2’ or ‘Level 1’are met, the likelihood of indoor air pollutionleading to health problems or discomfort in thebuilding is remote. Building owners andemployers therefore should endeavour to achieveLevel 2 of the IAQ Objectives as far as possible.

The intention of the EPD is clear. It is envisaged that thegeneral public, and hence, the hotel patrons, will takeIAQ of Level 2 as their minimum expectation.

While Level 3 at the back of the house is accepted legally,the complicated internal layout of the hotel may inducecross air flow from the back of the house that mayjeopardize the IAQ in the patron occupied areas andfunction rooms.

An IAQ to the majority satisfaction of the hotel patronswould therefore be the most salient sales point in termsof hotel quality.

IAQ ventilation rateobjectives…

The health objectives set guidelines for the prescribedpollutants that are deemed to be present in the indoorspace. Operational procedures to achieve these objectivesare to eliminate these sources, or, if they are present dueto some processes in the hotel, are to dilute thesepollutants by adequate ‘clean’ outdoor ventilation rate.


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Outdoor air is ‘clean’ or ‘fresh’ when its quality matchesor below the Hong Kong (Ambient) Air Quality Objectivesset out by HKEPD as in Table 3.

Table 3 Ambient Air Quality Objectives

Concentration in µµg/m3 (I)

Averaging TimePollutant

1 hr(ii)

8 hrs(iii)

24 hrs(iii)

3 mths(iv)

1 yr (iv)

Sulphur Dioxide 800 350 80

Total Suspended Particulate 260 80

Respirable Suspended Particulate (PM10)(v)

180 55

Nitrogen Dioxide 300 150 80

Carbon Monoxide 30,000

10,000

Photochemical Oxidants (as ozone) (vi) 240

Lead 1.5

(i) Measured at 25oC and 101.3 kPa (one atmosphere).(ii) Not to be exceeded more than three times per year.(iii) Not to be exceeded more than once per year.(iv) Arithmetic means.(v) Respirable suspended particulates means particles suspended in air with a nominal aerodynamic

diameter of 10 µg or less.(vi) Photochemical oxidants are determined by measurement of ozone only.Note: outdoor levels of Total Volatile Organic Compounds should be low (<0.1 mg/m3) if there are no sources.

Ventilation rate… The ventilation rate for clean outdoor air is also acontroversial matter. Figure 2 shows the variation of therecommended ventilation rate in l/s/person. The obviousreduction was in early 1970s under pressure from theenergy crisis. When the sick building syndrome issuearose, the rate has been increased to above 8 l/s/personin the late 1980s.

0

5

10

15

20

25

30

1860 1880 1900 1920 1940 1960 1980 2000

Year

Ven

tila

tio

n R

ate

L/s

.per

son

Smoking office

Figure 2. Historical Recommendation of Ventilation Rateper Person for Accepted IAQ.


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Conditions… In order that these rates to hold true, three conditionshave to be met:

• the outdoor air is clean according to the Hong Kong(Ambient) Air Quality Objectives;

• there is no pollutant sources indoors; and

• the occupants are healthy and they are not bacteriaor virus carriers.

The clean outdoor ventilation rate refers to the‘breathable’ rate, that is, the flow of clean or fresh air inand around the breathing zone, not the intake rate at theintake point.

In general, the fresh air is degraded along itspath of propagation from the intake point to thebreathing zone.

Outside airconditions…

When the situation matches the above conditions and nodegradation occurs, 8 to 10 l/s/person is deemed to beadequate to sustain an acceptable IAQ. Under thesecircumstances, the metabolic carbon dioxide at 1,000ppm can usually be used as a surrogate indicator ofacceptable IAQ.

It is worthwhile to point out that carbon dioxide is not apoisonous gas. A normal human being can be exposed tocarbon dioxide concentration as high as 30,000 ppm (3%)with mild effect provided no harmful pollutant is present.Ill effect occurs when oxygen level is reduced between15%-17% and below (normally associated withcorresponding CO2 3% and above). CO2 levels higher than1,000 ppm implies lower than 8 l/s/person outdoor airsupply rate at the breathing zone. Hence, inadequatedilution of pollutants occurs.

When it is known that some pollutants mayexist, such as where smoking is permitted, thereis high radon emission from building materials,insecticide or cleaning agents are used, higherventilation rate of clean outdoor air than thenorm should be provided.

Building sicksyndrome score…

Hotels often carry out surveys to their patrons requestingfeedback on their service. It may be worthwhile to includesurveys on the indoor environment. Such surveys can beconducted with employees. A simple questionnaire on theoccurrence of the following 10 symptoms arerecommended:


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q Block/stuffy or running nose

q Dryness of eyes

q Itching/watering eyes

q Dry throat/irritation of throat

q Difficulty in breathing/chest tightness

q Skin itching

q Headache

q Lethargy/tiredness

q Uneasiness

q Flu like symptoms.

From a large scale study conducted in 17 offices, abuilding sick syndrome score of 2 symptoms /person isthe criteria of acceptance. It implies 20% ofdissatisfaction. If higher quality is demanded, a criteria of1.5 symptoms/person is recommended.

Managing indoor airquality objectives…

The IAQ Health Objective is a set of guidelines to cap theconcentrations of common pollutants found indoors. Theguidelines also serve the purpose of certifying IAQ level byEPD. It must be noted that Tables 1 and 2 are notexhaustive. The compliance does not necessarilyguarantee good IAQ.

For example, asbestos may be present in asbestos-textured paints, ceiling tiles, pipe lagging, vinyl floor tilesand flexible joints in old hotels. Also, the Health Objectiveserves a goal to reduce health hazard. It is difficult to beused as a daily monitoring criterion for sustainingacceptable IAQ. Therefore, ventilation rates and metabolicCO2 are commonly used for monitoring IAQ. These aregood IAQ operation and maintenance targets. When inuse, the pre-conditions and the perception of ventilationrate at the breathing zone have to be attained.

The Building Sick Symptom Score is also a good indicatorof emergent IAQ problems. A programme for the hotelemployees to report building sick symptom is a goodfeedback for preventive maintenance strategy.

It can be seen that no single set of IAQ Objectivecan reasonably practicably serve the purpose ofsustaining an acceptable IAQ. A successfulmonitoring scheme will take into considerationthe three sets of IAQ Objectives to generate anoperational target. When the IAQ Objectives areset, the subsequent work will be to create an IAQmanagement strategy.


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IAQ ManagementStrategy…

steps!

The seven step IAQmanagementprogramme…

In the Guidance Note (GN) for Managing IAQ released byHKEPD, a seven step IAQ Management Programme isproposed. Although the GN intends to regulate IAQ inoffices and public places, the approach is equally wellapplicable to hotels. These steps are outlined below withapplication suitable for a hotel building.

Step 1…Allocation ofresponsibility andIAQ policy…

q Assign a person for the overall responsibility fordeveloping and implementing an IAQ managementprogramme.

• This person is usually the hotel manager or chiefengineer because they are vested with sufficientauthority to assume legal liabilities, assign resources,set investment targets and with a detailed knowledgeof the hotels.

• The IAQ manager can also be part of the duty of thehotel Health and Safety Officer, which might bemandated by the Labour Department.

q Combating adverse IAQ should be a top down actionas in many cases, IAQ is degraded due to ignorance ofemployees or ineffective policing of house rules.

q Clear instructions and job specifications should bemade known to all employees for their conduct andduty.

q Hotel customers should be advised of the impact oftheir behaviour within the hotel premises.

q It should be a policy of the hotel to train relevantpersonnel for updated knowledge on new legislation,codes of practice and IAQ standards.

Step 2…IAQ riskmanagement…

The person responsible for IAQ management should:

q Consider insurance cover through a third party policyto cover possible litigation from to serious IAQincidents.

q Study the GN and related IAQ literature to reach abasic understanding of factors that affect IAQ, and toelaborate this knowledge to colleagues in the hotel.

q Be aware of new and existing legislative requirementsand codes of practice.

• It is important also to interpret these requirementsrelevant to the operation of hotels, in a manner that isthoroughly understood by all the employees in theirrelevant context.

q Discuss with the hotel owners the IAQ objectives and


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plans to achieve these objectives, both for certificationpurpose and monitoring and control purposes.

q Use IAQ-related information from the building projectteam regarding ventilation design, building materialsused in construction, etc., and information about theoperation and maintenance in relation to the usage ofthe hotel in different areas for different activities.

q The need of different occupant groups should betaken as a priority of consideration.

q Matching users’ need in terms of safety, health andcomfort should be constantly monitored to predictpotential IAQ problems.

q If necessary, the building project team should beconsulted for any lack of information or clarificationof intention of the design and installation.

q Identify staff and contractors whose activities affectindoor air quality. Make a list of contact for peoplewho have involved in the construction and up-keepingof the hotel and its activities.

q Set up a protocol to approve building materials to beused in the hotel (refer to pollutant and sourceinventory form is provided in Appendix C of the EPDGN).

q Assign responsibilities for administering theprogramme to staff within the management team,while retaining overall supervisory control. Provideappropriate staff training and access to the GN andrelevant IAQ Objectives and manuals for designatedIAQ staff.

q Set up an IAQ emergency protocol for any outbreak ofIAQ problems, for example, outbreak of legionnaires’disease or discovery of excessive radon gas.

• A list of contact and emergency services should beposted in the management and engineering office.

q Make sure that more than one person in the hotel isfamiliar with the emergency protocol and that at leastone person can be found 24 hours to make importantdecisions concerning response to IAQ risks.

Step 3…Review of workcontracts andprocedures…

The IAQ manager should initiate or revise as necessary:

q Preventive and conditioned maintenance protocols forbuilding and equipment cleaning, maintenance, andrenovation work.

q Scheduling of cleaning, maintenance, renovationwork, and other activities that produce, retain,circulate, or cross propagate dust or other aircontaminants.

q Specifications for cleaning products, construction


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materials, furnishings, etc. to be used in the buildingand well document the Material Safety Data Sheets(refer to pollutant and source inventory form providedin Appendix C of the EPD GN).

q Policy on tobacco smoking, e.g. the areas wherecustomers are and are not allowed to smoke andconstantly review the policy of such requirement.

q Common sense rules to hotel customers andconstantly review the policy of such requirement.

q Procedures such as closed air isolation of renovationwork areas, workshops, car parks, grease tanks,kitchens, laundries, beauty saloons or areas wherecertain specific pollutants are produced.

• Provide independent exhaust of dust and other aircontaminants in these areas.

q Highlight the legal responsibilities to contractors andtenants who might trigger an IAQ crisis or problems.

Step 4…Review of occupationcontracts…

The IAQ manager needs to define shop and restauranttenants’ responsibility for IAQ and, where appropriate,insert requirements in occupation leases. The managershould consider requiring their tenants to:

q Inform management of alterations (e.g. partitionrelocation) and redecoration plans.

q Inform management of dates and duration of anydecoration or alteration work.

q Ensure furnishings and office equipment are placedwhere they will not obstruct ventilation.

q Inform management of changes in occupation density.

q Inform management of exhibits or activities that mayattract an abnormal attendance.

q Inform management of material used especially thoseemit health affected contaminants or objectionableodour.

q Assist in any IAQ investigation when required.

Step 5…Communication… The IAQ manager should develop, document and

communicate policy for (refer also to Section 6 of EPDGN):

q Notifying of activities likely to generate odours andindoor air pollutants.

q Reporting any spills, leaks, or strong smells.

q Receiving and responding to indoor air complaints.

q All employees understand their roll with respect toIAQ emergency actions.


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q Circulate updated information to relevantinformation, company policy on managing IAQ,special events with IAQ risks and etc.

q Include IAQ information pamphlets in the hotelinformation binder.

Step 6…Investigation ofcomplaints…

The IAQ manager should develop and documentprocedures for (refer also to Section 7 of EPD GN):

q Communicate clearly to relevant personnel that anyinvestigation is case oriented. The investigation islooking for system faults rather than human faults.

q Conducting an initial walk-through investigationespecially for the outdoor air system (see Section 4.2in this document).

q Communicating on the progress of an investigationand conducting interviews as part of an investigation.

q Making more detailed assessments and environmentalmonitoring.

q Engaging outside professionals if necessary.

Step 7…Record keeping… The IAQ manager should:

q Keep up-to-date records of IAQ complaints and follow-up action.

q Use past cases to educate the hotel personnel.

q Register advice or warnings where appropriate torelevant personnel, contractors for mistakes givingrise to serious IAQ risks.

q Obtain Material Safety Data Sheets (MSDS) formaterials used and stored in the building.

q Endeavour to incorporate IAQ management within thehotel’s Environmental Management System.

Walk-throughsurvey…

In practice, any problem investigation by experienced IAQmanager or consultant is not welcome by the hotelmanagement team because the team is always accused ofnot performing their job properly. Any walk-throughshould be targeted towards finding and solving systemfaults rather than apportioning human error. To dootherwise will reduce the co-operation from staff in-charge. This should be communicated to all partiesconcerned.

There are two good reasons to conduct a walk-throughinvestigation by an experienced IAQ manager:

• 90% of the IAQ problems can be identified, hence,mitigation measures can be planned and


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implemented;

• any measurement for IAQ level certification purposeshould be done with all the inadvertent faultsmitigated.

Faults are recorded as system inherent faults andhuman inadvertent faults.

System inherent faults are most likely due to:

• design faults;

• commissioning errors;

• wrong operation and maintenance procedures as laiddown in the manuals;

• demand not matching facilities provided due tochange of usage;

• degradation of system performance;

• accumulation of dirt and growth of microbes in air-ducts and conceal areas;

• inadequate access to problem areas;

• air pressure not balanced or adjusted correctlycausing cross contamination;

• change of internal layout causing cross flow betweenhigh pollutant load zones and critical zones;

• contamination of outdoor air system due to adverseoutdoor environments;

• contamination of linen products by dust mites andmildews;

• insufficient control of pests, rats, cockroaches etc.,especially in the labyrinth of ductwork, duct-shafts,vent-shafts, pipe ducts, etc.

• wrong location of grease tanks for restaurantscausing leakage of odour and bacteria to circulationarea;

• unnecessary provision of floor drains, pipe ductdrains which allow release of foul air from soil ventpipes due to drying of U-traps in these drains;

• burst of ‘odour bomb’ due to full bore flow in blackwater pipes and insufficient soil pipe vents;

• leakage of odour from soil sumps;

• undersize and caulking of drain pipes for air handlingunits and fan coils;

• IAQ problems due to internal lining of ducts and airside equipment.

Human inadvertent faults are most likely due to:


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• unknown additional pollutants brought in by hoteltenants and customers;

• pollutant generation due to renovation or by otherhotel general and special contractors;

• insufficient cleaning processes;

• inadvertent spill over, leakage or purging of pollutantsources;

• insufficient maintenance of U-traps in drains and soilpipe vents;

• poor maintenance of the air handling unit and fan coilcondensate pans and drains;

• poor water treatment to indoor water features,condensate pans, calorifiers, water tanks for drinkingwater and fire services tanks

• release of pollutant material in the air flow pathsespecially the outdoor air flow paths

These lists can never be exhausted. The IAQ manager candevelop a check list of his own tailor made to the hotelusing the above as a guide.

The IAQ manager can also develop different lists fordifferent incidences in the investigation to improveproficiency under different circumstances.

The following section provides illustrations of what canhappen in buildings in Hong Kong.

Diagnosis of IAQproblems from awalk-through surveyof the fresh airsystem…

General… No two hotels are identical due to the complexity of thelocation, hotel forms and expressions, use of material,internal layout and decoration, management culture,types of customers, building services systems etc.

There is no single diagnosis protocol of IAQ problems andrisks suitable for all hotels. However, it is feasible toconfigure the system in a general sense. A tailor madeprotocol is then developed on this base configuration.This section is dedicated to this method.

Why fresh airsystems?

In practice, it is very seldom that specific filtrationsystems other than particulate filters will be used for pre-cleaning the outdoor air or cleaning the re-circulated airbefore it is distributed to the breathing zone.

The axiom of “Solution to Pollution is Dilution” stillpredominates in most building ventilation systemdesigns. Therefore the fresh air system is very important.


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The term ‘fresh air’ is used here to imply that the qualityof the outdoor air taken into the system complies with theHong Kong (Ambient) Air Quality Objectives.

Following a study of over one hundred buildings in HongKong, a general configuration is used to model all thedesign of the fresh air system.

First of all, there are two types of fresh air intakes:

• Individual floor intake – where the fresh air is takenindividually on each floor and supplied to the spaceon the same floor.

• Central intake – where the fresh air is drawn in by afresh air fan (FAF) or a primary air unit (PAU)installed on the roof and refuge floors.

Most of the fresh air distribution systems in hotels arecentralised. The following illustrations are based onsurveys of these systems. If the basic configuration is wellunderstood, the diagnosis of the individual floor intakesystems will be the same.

Furthermore, the intake equipment serving hotels arePAUs. The difference is that it is completed with a coolingand/or heating coil to pre-conditioned the air to or closeto the room air thermal conditions, before being mixedwith the return room air.

There are a number of hotels using only one centralintake system to serve all the guest rooms. It imposes aninherent air balance difficulty and is not a good practice.

Many of the systems have central PAUs supplying pre-treated fresh air to the air handling units (AHU) or mostoften room fan coil units (FCU) through the fresh airdistribution stack.


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Figure 3. A typical central fresh air system

This system is configured into four tiers for ease ofinvestigation. A tier is a part of the system, which has itsown forms of air degradation.

The output from one tier is input into the subsequent tiercarrying the degraded air along.

The following configuration explains the distribution ofthe fresh air into each individual guest rooms. Fresh airsystem for function rooms and back of the house followsthe same logic.

Tier

This comprises of the front-end devices such as louversand pre-filters. The outdoor air intake into the system issubjected to pre-contamination by the environmentalconditions. The front-end devices are either ducted intothe PAU which is configured as the front end equipment,


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or open into the PAU room. In the former case, air isaffected by the cleanness of the ductwork. In the lattercase, air is affected by the pollutants in the PAU room, orin the space in the refuge floor. Furthermore, the airquality is affected by the cleanliness of the front-endequipment.

Tier

This is the central distribution ductwork connecting thefront-end equipment/room to the rear end equipment/room on individual floors. Most often, the maindistribution duct goes down the duct shaft and branchesoff on each floor. The individual floor duct branches runalong the corridor and ducts into the FCU in eachguestroom.

A simple volume control damper balances the designedamount of fresh air. The system is inherently very difficultto balance. A constant flow valve is shown here which canimprove the air balance. However, it is only mainly usedin large AHU rooms and no case that it is used in hotelguestrooms.

Tier

The fresh air from the branch duct is either ducted intothe return air plenum of the FCU in the guestroom, or issimply opened into the ceiling plenum close to the returninlet of FCU.

In the former case, air is affected by the cleanness of theduct. In the latter case, air quality is affected by thecontaminants present in the ceiling plenum.Furthermore, air quality is affected by the cleanness ofthe rear end equipment. In the rear end side of the larger


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systems such as those serving function rooms, the rearend equipment is more complicated comprising other airconditioned devices, such as humidifiers, dehumidifiers,etc.

Tier

This tier is the part of air circulation in the guestroom.The type of distribution mainly used is perfect mixing.Other possible ways of fresh air distribution in otherspaces are displacement type, push and pull, or evendirect supply of pre-conditioned fresh air into space.

Each type of air distribution has different ventilationeffectiveness. Perfect mixing is the most common. In theroom space, air quality is affected by infiltration throughbuilding fabric, windows, and openings and cross flowbetween spaces.

Degradation of freshair…

Three types of degradation can occur in each tier:

• Pre-contamination: the fresh air is pre-contaminatedbefore reaching the breathing zone by the immediateenvironment. The key is cleanliness of the system andpollutants emitted in that particular tier.

• By-pass of fresh air: fresh air in this tier is by-passed to somewhere else instead of going along thesystem to the breathing zone. The by-passed fresh aircan either be replaced by foul air in the space, in thesystem, or without replacement.

• Short-circuit with foul air: foul air outside of thefresh air system is being short-circuited into the freshair system contaminating the fresh air. The foul airmay even displace some of the fresh air or simply addonto the fresh air stream.

It is sometimes quite confusing in using the terms by-pass and short-circuit. In the context of fresh airdegradation, by-pass always refers to by-pass of fresh airout of the fresh air system, while short-circuit alwaysrefers to short-circuit of foul air into the fresh air system.


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Examples ofdegradation of freshair in Tier 1…

Pre-contamination of thefresh air by vehicularemission and industrialeffluence.

Vehicular borne pollutantsbeing trapped in canyonstreets formed by high risebuildings on a busy street.

A typical example of pre-contamination fromconstruction and in manycases by effluence fromcooling towers.

Pre-contamination by dirtand mildew growth onintake louvers and birdscreens.


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In the refuge floor where thefresh air intake locates, thespace is used for storage ofbuilding material where thefresh air stream picks upparticulates from ceilingtiles, fibre glass and usedpaints in open buckets.Radon level can also be highbecause of the emissionfrom the walls.

A bucket of paint andcigarette buds found insidea PAU room! The air ductappear in the photographclearly identifies that it is afresh air duct (FAD). ThePAU intake is opened intothe plant room. The peoplein rooms served by thisfresh air plant complainedabout the ‘unknown’sources of irritating gases.

A short-circuit case asdemonstrated by the closeproximity of the exhaustand supply louvers. Theshort-circuit will be veryprominent if the wind is inthe right direction.

A typical by-pass case in thePAU where poorworkmanship left a big holein the air plenum causingby-pass of fresh air into‘somewhere’.

Hole

Shown below is a typical vertical profile of the pollutantsin a canyon street bounded by high rise buildings up to45 storeys on one side in Central district.

The pollutant concentration approaches the background


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roughly at 20th floor up. The street level concentrationscan be several folds higher. The same profile applies to allother pollutants. It demonstrates the importance ofstrategically locating the fresh air intake.

y = 524.04x-0.0652

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A typical short-circuit case of a five star hotel on theHong Kong Island. Although the supply and exhaust airare on opposite sides. For aesthetic reasons, the highparapet wall forms a short-circuit horse track.


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Examples ofdegradation of freshair in Tier-2…

Pre-contamination due todamage of insulationmaterial.

Dampers used for balancingfresh from Tier 2 to Tier 3are prone to short-circuit ofspace air into the systemdue to improper air balancein the rear end equipmentroom or rear end FCUplenums.

Serious by-pass of fresh airoccurs at leaky access doorsor panels.


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Serious pre-contaminationbefore the rear end AHU dueto dirt and accumulation ofcondensate.

Pre-contamination frombuilding material, paintsand cleaning agents.Sometimes, contractorssmoke in air handling unitrooms to enjoy the fresh airwhile contaminating it! Onecase has been identified thatthe fresh air intake room isused as resting place forworkers.

Very leaky supply airplenum at the bottom of theductwork.


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Dirty diffusers indicatesstrongly the pre-contamination in the spacedistribution ductwork, otherthan the existence ofpollutant sources fromindoor activity, radon fromwalls, infiltration frombuilding fabric, windowsand openings and cross pre-contamination betweenzones due to cross flowinduced by pressure forcesinside the hotel.

Short-circuit in Tier 4 ismost prominent in case ofcorridor common return.

Fresh air can easily by-passed if the fresh air orsupply air plenum is sharedwith leaky cable trays andconduits.


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Ozone, VOCs andparticulate emission fromoffice equipment is verycommon even in hotels.These contaminants willfollow the air flow in spaceand propagate into criticalzones.

Generation of dust andVoCs in a renovated room. Ifno dedicated exhaust isprovided, the contaminantscan easily travels to otherspaces.

How much better canwe get?

There are numerous examples of Hong Kong buildings inwhich the fresh air has been degraded to an unacceptablelevel.

An investigation into the consequences of the degradationreveals that only one-third equivalent of the fresh air isbeing delivered to the breathing zone. If the same airquality is maintained, three times more fresh air of thedesigned amount is required!

Most of the examples shown can easily be identified andrectified. It is shown how easily the targets for bothenergy conservation and acceptable IAQ can be achieved.


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Measurement…

A detail measurement for thecertification can be conductedafter all the mitigationmeasures for the inherent andinadvertent faults are rectified.Some of the pollutants such asVOCs are costly to measure.Therefore, it has to be doneright the first time. It is also thereason for a walk-throughinspection before employing aspecial IAQ consultant orcontractor for suchmeasurement. The photographon the left shows how VOC issampled in cannister in the sitefor a GCMS analysis later inthe laboratory.

At times, it is important tomonitor the IAQ by at leastsome simple measurements.The photograph shows amonitor for dustmeasurements.

Instruments formeasurement of CO2, CO,air temperature and relativehumidity.


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Other Government Departments Policing theIndoor Air Quality

Table 4. Summary of Responsibilities of Government Department Relating toIndoor Air Pollution (HKEPD)

Department Legislation Relevance to IAQ

BuildingsDepartment

Buildings OrdinanceCap. 123

Requirement for mechanical ventilationwith 5 air changes per hour to officenot provided with natural ventilation.

Public Health &Municipal ServicesOrdinance, Cap. 132

Dampers, filters & precipitators areinspected yearly by registeredventilation contractor.

Specified ventilation rates for scheduledpremises.Provisional

Urban/ProvisionalRegional Council

Places of PublicEntertainmentRegulations, Cap. 172

Requires provision of sufficientventilation to the public places.

A fresh air supply requirement of13m3/h/person is imposed on allentertainment machine centres.

Factories & IndustrialUndertakingsOrdinance, Cap. 59

Requirements to protect workers(workplace safety and measures of workpractice as well as medicalsurveillance).

Labour DepartmentOccupational Safety &Health Ordinance,Cap. 509

Requires the provision of safe andhealthy workplace for industrial andnon-industrial workers. Provision ofadequate ventilation & air withinworkplace should be kept free ofimpurities.

Various governmentdepartments such asCommission ofPolice, TV &Licensing Authority

Smoking (PublicHealth) (Amendment)Ordinance, Cap. 371;Code of Practice underBroadcastingAuthority Ordinance

Control measures relating toprohibition of advertisements,designated ‘No Smoking’ areas, ‘NoSmoking’ signs, etc.

Customs & ExciseDepartment

Consumer GoodsSafety Ordinance,Cap. 456

Ozone LayerProtection Ordinance,Cap. 403

Air Pollution ControlOrdinance, Cap. 311

Control of import of consumer goodswith focus on product safety andenforcement of import control on ozone-depleting substances & asbestosthrough import licensing (as authorisedby EPD).

Agriculture &FisheriesDepartment

Pesticides Ordinance,Cap. 133

Control of import, manufacture, supply& sale (but no control of use ofregistered pesticides).

EnvironmentalProtectionDepartment

Air Pollution ControlOrdinance, Cap. 311

Established Air Control Zones and theassociated Air Quality Objectives

Control of asbestos in environment.


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Further reading…

References… • "Guidance Notes for the Management of Indoor AirQuality in Offices and Public Places" by Indoor AirQuality Management Group, the Government of theHKSAR.

• "Managing Indoor Air Quality – A Consultation Paper"by Indoor Air Quality Management Group, theGovernment of the HKSAR.

• "Indoor Air Quality and You" (Leaflet) by Air ServicesGroup, Environmental Protection Department, theGovernment of the HKSAR.

• "Formaldehyde and You" (Leaflet) by Air ServicesGroup, Environmental Protection Department.

• "Environmental Tobacco Smoke and You" (Leaflet) byEnvironmental Protection Department.

• "Biological Contaminants and You" (Leaflet) byEnvironmental Protection Department.

• "Volatile Organic Compounds and You" (Leaflet) byEnvironmental Protection Department.

• "Radon and You" (Leaflet) by Air Services Group,Environmental Protection Department.

• "Control of Radon Concentration in New buildings"(ProPECC PN 1/99) by Environmental ProtectionDepartment.

• "Improve the Indoor Air Quality in Your Building" byEnvironmental Protection Department.

• "Improve the Indoor Air Quality in Your Home" byEnvironmental Protection Department.

• "Code of Practice – Prevention of Legionnaires’Disease" by Prevention of Legionnaires’ DiseaseCommittee, Electrical and Mechanical ServicesDepartment.

• "Control of Oil Fume and Cooking Odor fromRestaurants and Food Business" by EnvironmentalProtection Department.

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