Commercial Kitchen Exhaust System Design Sponsored by AOM Upcoming - - PowerPoint PPT Presentation

Welcome to the AIRAH Vic Divisional Seminar

Commercial Kitchen Exhaust System Design

Sponsored by AOM

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Tonight’s Speaker: Sven Bolomey, M.AIRAH Air & Odour Management Australia

Who is AOM Australia?

7

Air and Odour Management Australia

General Industry Trends

What to expect in the future of hospitality

8

General Industry Trends

What to expect in the future of hospitality

9

• Australia’s ‘foodie culture’ is expected to underpin

revenue growth in the restaurants industry in the next five years to 2022.

• Food service delivery seen as an opportunity and a

threat

• The evolution of Australia’s pubs from watering

holes to gastronomy destinations is seeing publicans draw a growing proportion of revenue from food

• Overseas visitors are increasingly turning to

Australia for holidays with arrivals increasing by 7.1% in the year to November 2017

• The lower exchange rate is also encouraging

domestic travellers (domestic overnight visits increasing by 7.2% )

What is commercial kitchen exhaust?

10

Vapour / Grease vapour Particulate Matter (PM)

Ultra Fine (<0.1 micron) Fine (0.1-1 micron) Coarse (>1 micron)

Volatile Organic Compounds (VOCs)

hydrocarbons, alcohols, phenols, aldehydes, ketones, n-alkanoic acid, n- alkenoic acids, carbonyls, etc.

Polyaromatic Hydrocarbon (PAH), CO, CO2, NO2, SO2 Heat + particles + gases

11

What is commercial kitchen exhaust?

Particle Matter profile during a heavy Type 4 cooking process

0.00E+00 2.00E+08 4.00E+08 6.00E+08 8.00E+08 1.00E+09 1.20E+09 190 210 230 250 270 290 310 330 350 370 390

Particle c concentration (num number/m3) Cooking t time ( e (sec ec)

0.3 µm 0.5 µm 1.0 µm

Size ze (µm) m) Pr Prop

• por
• rtion

ion 0.3 50.20% 0.5 43.80% 1 6.18% 5 0.24% 10 0.02% 25 0.01%

TOTAL P PM C CONCENTR NTRATION N

Particle (0.3,0.5, 1.0 µm) profile (without treatment)

Xia Zhong (University of Sydney), Sven Bolomey (AOM Australia), Commercial kitchen exhaust contaminant removal using combined treatment techniques and filtration efficiency assessment with developing standardised testing protocol, AIRAH Presentation Future of HVAC 2018

12

What is commercial kitchen exhaust?

Odour composition is complex, more than 65 VOC compounds were detected.

• More than 50% compounds can

be smelled by panellists, but only ~25% compounds were effectively tied to an odour description.

• Other identified odours include:

rancid, putrid, faecal, burnt fat, decay, burning protein, burning, plastic, basoline, petrol. These are not associated to compounds.

Corresponded c compound f from M MS Concentration (μg/m3) Identif ifie ied O Odou

• ur D

Descrip iption

• n

Aceto tone 82.7 Sweet, chemical Penta tadiene 54.1 Burning Buta tanal 205.4 Chemical, solvent Buta tanal 205.4 Solvent Benzene 268.4 Solvent, sweet Cyc ycloh

• hexene

34.4 Burning, rancid Heptane 614 Solvent Vinylcyc yclo lopentan ane 17.9 Solvent Toluene 61.8 Solvent (Painting) Tr Trans-1-Bu Butyl-2-me methyl ylcyclop

• propan

ane 169.6 Continuation of burning to solvent Hexan anal al 245.3 Rancid to grassy 2-Hepta tanone 50.7 Fruity Hepta tanal 237.3 Milky Phenol

• l

391.8 Sweet Octan anal al 79.5 Sweet, fruity

What are the potential impacts of commercial kitchen exhaust?

Health Effects of Particle Matter

13

What are the potential impacts of commercial kitchen exhaust?

Environmental Impact – Potential high local impact on urban air quality

14

Nikhil Pubby (Monash University), Estimate the level of compliance for non-residential kitchen exhaust systems in Melbourne CBD and evaluating the causes and effects of increasing air pollution due to these systems – Initial Finding, AIRAH Internship, 2019 CFD analysis of the discharge point effluent

What are the potential impacts of commercial kitchen exhaust?

Environmental Impact – Potential high impact on urban air quality

15

Published in AIRAH Ecolibrium article on Kitchen Exhaust Design, March 2018

“The average diesel engine truck on the road today would need to drive for 10 miles (16km)

• n the freeway to put out the same mass of particles as a single charbroiled hamburger patty.”

University of California

“ In New York the emissions from char broilers contributed to more than 12,5% of PM2,5 attributable deaths annually in the period 2005-2007. This equates to 400 deaths per year.”

Department of Health and Mental Hygiene

What are the potential impacts of commercial kitchen exhaust?

Safety Risk - Fire

16

“I believe there was a fire

• n the grill and it had

gotten a bit bigger than they expected,” Mr Carrigg said

What are the potential impacts of commercial kitchen exhaust?

Safety Risk - Fire

17

• In a generalized scenario: abnormal event will take place on a cooking surface (where

excessive heat and flames are present) to create a flare-up.

• The most common source of a flare-up is the ignition of cooking oil vapors that come

in contact with flames or excess heat.

• This flare-up produces high reaching flames that contact and/or quickly heat the hood

and filters.

• If the flare-up is intense enough or sustained over a sufficient period of time

(approximately 2 minutes) the flame can ignite residual grease accumulations commonly found in the hood/duct area.

• Second the ignition of combustible materials (generally wood building materials or

cardboard storage containers) that are too close to the radiant heat energy being emitted from the metal exhaust duct can cause the fire to propagate

Status of Commercial Kitchen Ventilation in the Australian HVAC Sector

Key documents and initiatives

18

AS/NZS ZS 1668. 1668.1: 1:2015 015 The use of ventilation and air conditioning in buildings Fire and smoke control in buildings AS 1668. 1668.2-201 2012/ 2/Amdt 2-2016 2016 The use of Ventilation and Air-conditioning in buildings Mechanical ventilation in buildings AIRAH: Increasing awareness of Commercial Kitchen Exhaust in overall HVAC Sector: Future of HVAC, Ecolibrium, Technical Bulletins, Technical Group Buil ildin ing r ratin ing s systems: Green Start “Emissions” for both Design & Construction And Building Performance

Status of Commercial Kitchen Ventilation in the International HVAC Sector

USA and Europe leading way forwards – Opportunities in Asia

19

USA SA

• ASHRAE Standard Project Committee 154 - Ventilation for Commercial Cooking Operations
• ASHRAE Standard 154-2003R, Ventilation for Commercial Cooking Operations (Revision)
• National Fire Protection Association: NFPA 96 Standard for Ventilation Control and Fire

Protection of Commercial Cooking Operations

• UL standards: On specific elements to Commercial Kitchen Ventilation (Filters, Exhaust hood,

Fan, etc.) Europe European Standard applicable to all EU members BS EN 16282-1:2017 - Equipment for commercial kitchens. Components for ventilation in commercial kitchens. General requirements including calculation method. As Asia: : Application of UL Standards but no clean design standard

CKV Projects: An abundance of Stakeholders

20

Conc ncep ept ( (DA DA) Archi hitec ect / / BCA Revi eview BSE / M Mechanical E Eng ngine neer er Equipment S Supplier Kitche hen C n Cont ntractor / / Designe ner Mecha hani nical C Cont ntractor Equipment S Supplier Mecha hani nical C Cont ntractor / / Engine neer / Equipment S Supplier Owner / / End U User Kitche hen S n Staff Clea eaning ng C Compa panies es Equipment S Supplier Kitche hen D n Designe ner Kitche hen C n Cont ntractor Des esig ign (Constr tructi tion Certificate) e) Inst stall (Compliance e Certificate) e) Commissi ssioning (Commissi ssioni ning Certificate) e) O&M / / Servi vice (Compl plianc nce Certificate) e) Coun uncils Planni nning ng Aut uthorities es

Counci uncils Building ng Certifier er

Build ilding C Cer ertif ifie ier Build ilding C Cer ertif ifie ier Buildi ding ng Man anag agement

Main challenge – Working at Interface between Kitchen and Mechanical System

21

CKV Projects: A multitude of different Projects

With a multitude of different issues

Base Build Design

Designing “blindly” with building constraints (star ratings, developer requirements).

Tenancy Design

Specific exhaust system requirements which may be difficult to integrate into a building design.

Hotel Design

Major projects with important exhaust requirements which may be difficult to integrate into developments

Different elements to commercial kitchen system design

Which we will look into further from a design perspective

22

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Discharge Point Identification

The main way to limit any potential Impacts

23

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

24

Discharge Point Identification

Constraint : AS 1668.1-2015

Ducts should be vertical and take a direct route (or as short as possible) to the outside.

25

Discharge Point Identification

Constraint : AS 1668.2-2012 defines requirements to discharge of commercial kitchen exhaust

• Airflow < 1000 l/s : not deem

emed ed o

• bjec

ectionable le No c constr traints ts othe ther tha than t to no not t create a a nuisanc nce a and d respe pect m minimum um sepa paration n distanc nces

• Airflow > 1000 l/s : dee

eemed ob

• bjectio

ionable le Major c r cons nstraints to discha harge p point t thoug ugh h Engin ineered Solu

• lutio

ion a allo lows f for

• r con
• ncessions a

as per er C3. 3.10 10.3

• Odour and smoke reduction through

independent testing

• Calculation of Deemed Airflow Rate
• Routine testing and maintenance

26

Discharge Point Identification

Different Options – No perfect solution

27

Discharge Point Identification

Advanta tage ges Disad advan antag ages

• $$$
• Can be (very) difficult to implement

particularly on large developments: long horizontal ducts, large air volumes, long distances.

• Spatial and access requirements
• Fully Compliant
• Does not require any form of filtration

1 – Vertical Discharge

Ideal for standard Apartment block / ground floor tenancies type of development

28

Discharge Point Identification

Advanta tage ges Disad advan antag age

• Potential for nuisance at and above podium

level

• Might require filtration
• Spatial and access requirements
• Potential to be fully Compliant

(separation distances)

• Might not require any form of filtration
• Less distance to travel to discharge

2 – Podium Level Vertical Discharge

Often used in conjunction with filtration equipment in new developments with significant exhaust requirements (F&B tenancies) in lower floors Exa xample: http://www.aomaus.com.au/projects/east- village/

29

Discharge Point Identification

Advanta tage ges Disad advan antag ages

• Non compliant – requires an Engineered

Solution (filtration) to treat the exhaust

• Potential for nuisance
• Potentially easier and cheaper to

implement than vertical discharge

• Often located so as to minimise potential

nuisance of the kitchen exhaust

3 – High level horizontal discharge

Often used in new and retro fit developments to find a reasonable solution to discharging commercial kitchen exhaust whilst minimising the risk of nuisance. Exa xample: http://www.aomaus.com.au/projects/aom- project-w-hotel-brisbane/

30

Discharge Point Identification

Advanta tage ges Disad advan antag ages

• Non compliant – requires an Engineered

Solution (filtration) to treat the exhaust

• High potential for nuisance
• Regular maintenance
• Constraints to type of cooking in tenancies
• Potentially a lot easier and a lot cheaper

to implement than vertical discharge

• Can be adapted to the requirements of

the tenancy

4 – Low level horizontal discharge

Often used in retro fit developments with limited

• ptions to managing commercial kitchen exhaust.

Discharge point location and filtration design are crucial elements to minimising the risk of nuisance. Exa xample: http: p://www.aomaus.com.a .au/projects/pa pacific ic- bo bondi ndi-beac ach-dev evel elopmen ent/

31

Discharge Point Identification

4 – Low level horizontal discharge

32

Discharge Point Identification

4 – Low level horizontal discharge

33

Discharge Point Identification

Distance to Intakes and Deemed Airflow Rates

• Deem

eemed ed Airflow R Rate = e = Actual Airflow R Rate e – (Frac action ional E al Effic iciency y x Actual A al Airflo low R Rate)

• Fractional Efficiency = Independent testing of
• dour filtration processes from commercial

kitchen airstream.

Cooking Type Constraints

Impact of Cooking Types on overall system design

34

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Cooking Type Constraints

AS1668.2-2012 Classification to cooking Types – leads to airflow calculations

35

• ASHRAE Standard uses similar classification: Light, Medium, Heavy, Extra Heavy Duty Equipment
• EU Standards: Airflows based on cooking equipment

Cooking Type Constraints

Significant differences in exhaust contamination between cooking equipment

36

Schrock, D.W., et al., A New Standard Method of Test for Determining the Grease Particulate Removal Efficiency of Filter Systems for Kitchen Ventilation. ASHRAE Transactions, 2006.

Cooking Type Constraints

PM and VOCs concentrations vary importantly between commercial kitchen equipment and food sources5: type of equipment, cooking method, cooking temperature, type of food, fat content.

37

Cooking Hambu burger er Auto- Chargrill ill Hambu burger er Under er- Chargrill ill Steak Under er- chargrill ill Chicke ken Under er- Chargrill ill Hambu burger er Gridd iddle le Chicke ken Gridd iddle le

PM(mg/kg) 4488 15026

(250 g/burger – 200 burgers – 50 kg meat x 15 = 0.75kg PM)

7821 7202 Nq nq VOCs (mg/kg) 7.24 30.48 22.57 27.90 2.61 9.51

5: MacDonald et al., 2003, Emissions from Charbroiling and Grilling of Chicken and Beef. Journal of the Air & Waste Management Association, 53:2, 185-194 nq: not qualified. Data missing in the test.

38

Cooking Type Constraints

Chargrill and Solid Fuel – Extra Heavy Duty Equipment that is the most difficult to manage

0.00E+00 2.00E+08 4.00E+08 6.00E+08 8.00E+08 1.00E+09 50 100 150 200 250 300 350 400

Particle c concentration (numb mber/m3 m3) Cooking t time ( e (sec ec)

Partic icle le (0.3 µm) pr profile le

Witho hout ut tre reatme ment HCF CF + Doubl ble ES ESP tre reatme ment

Xia Zhong (University of Sydney), Sven Bolomey (AOM Australia), Commercial kitchen exhaust contaminant removal using combined treatment techniques and filtration efficiency assessment with developing standardised testing protocol, AIRAH Presentation Future of HVAC 2018

Cooking Type Constraints

AS1668.2-2012 requirements related to Solid Fuel Exhaust

39

Cooking Type Constraints

Example of a wood fired pizza oven discharging horizontally without any treatment

40 Project Audit after significant local complaints underlined that in additional to non compliance to AS1668.2- 2012, the discharge was non compliant to Environmental Protection Act 1994 which requires discharges to be:

• below 5ou for odour and staying
• below 15ppm for carbon monoxide. (i.e. 6 ppm rise over ambient).
• capture any of the BTEX group (i.e. benzene, toluene, ethylbenzene, and xylenes – chemicals found in

solvents or petrochemical situations).

Filtration System Design

Current state of filtration system design

41

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

42

Filtration System Design

AS 1668.1-2015 defines requirements to filtration of commercial kitchen exhaust

1.6 S System O Obje jecti tive Systems designed in accordance with this Standard are intended, for a single fire event, to achieve the following (….) (e) Restrict the initiation of fire within ductwork. (f) Restrict the spread of fire and smoke within ductwork. 6.2.9 F Flame a and S Spark Arre rest stance Where the length of an exhaust duct within the building exceed eeds 1 10 m and where an exposed ed f flame o e or ember ers may be present as part of the cooking process, devices that prevent the spread of flames in accordance with UL 104 1046 shall be incorporated into kitchen exhaust hoods (or filtration systems). UL 1 1046 provides the f following k key s sta tate tements ts w with r regards t to the a e above: e: Construction 6 General 6.2 Parts of grease filters that are exposed t to cooki king e effluent shall b be c constructe ted o

• f non
• n-combustible m

mate terials.

43

Filtration System Design

AS 1668.1-2015 defines requirements to filtration of commercial kitchen exhaust

• When in doubt, use filtration equipment (in hood or in duct) made of non combustible

material as per UL1046 / AS 1530.

• Filters are to precipitate grease as opposed to holding grease to restrict the spread of

fire in the duct work.

44

Filtration System Design

AS1668.2-2012 - Mechanical ventilation in buildings Filtration System Design Overall Objective: Remove the Particle Matter to mitigate Odour.

“ “

45

Filtration System Design

Three main scenarios related to location of discharge point and risk of nuisance

• 1. First s

scenari rio: “ : “Do Do nothi hing ng” - Gene neral T Tende dency - mo moving a away from m this a approach ch

• Compliant to Australian Standards
• 2. Second

nd s scena nario: “ : “Volun untary Treatment” – Filterin ing P Partic icle le M Matter

• Compliant to Australia Standards
• Objective to decrease air quality impact: highly contaminated / high discharge airflow
• Objective to decrease risk: grease and fire

Example: http://www.aomaus.com.au/projects/spice-temple-rockpool-group/

• 3. Third s

d scena nari rio : : “Compu pulsory T Treatment”- Filteri ring ng P Particle M Matter a r and d removing ng O Odour ur

• Non Compliant discharge
• Objective is to meet the requirements of AS1668.2-2012 Concessions

Example: http://www.aomaus.com.au/projects/ribs-burgers/

46

Filtration System Design

AOM Engineering Bulletin 0004 Cooking types and filtration needs

47

Advanta tage ge Disad advan antag age

• Risk of over engineering - increased capital $

$

• Potential to under engineer
• Cost of the servicing can be high $
• Spatial and access requirements
• Filtration located far from the source of

contaminants (plant room design)

• Clear Responsibility
• Filtration equipment outlives the tenant
• Maintenance is included in building works

Equipping filtration systems within the base build design

Filtration System Design

48

Advanta tage ge Disad advan antag age

• Difficult to implement (tenant push back $)
• Potential for multiple systems
• Maintenance depends on the tenants
• Is flexible with changing tenants
• Exhaust and treatment design specific to tenancy

cooking

• Treatment close to source
• Specific design relates to cheaper capital cost
• Is flexible with changing tenants

Imposing filtration systems at the tenancy level

Filtration System Design

Ultimately it is the building owner that holds the regulatory responsibility for fire safety at the premises.

49

Filtration System Design

Potential Efficiencies to filtration equipment

0.00E+00 2.00E+08 4.00E+08 6.00E+08 8.00E+08 1.00E+09 50 100 150 200 250 300 350 400

Particle c concentration (numb mber/m3 m3) Cooking t time ( e (sec ec)

Partic icle le (0.3 µm) pr profile le

Witho hout ut tre reatme ment HCF CF + Doubl ble ES ESP tre reatme ment

50

Filtration System Design

Potential Efficiencies to filtration equipment Filtration ion e effic iciency ( y (%)

0. 0.3 µ 3 µm 0. 0.5 µ 5 µm 1. 1.0 µ 0 µm 5. 5.0 µ 0 µm 10. 10.0 µ µm 25. 25.0 µ µm

HCF HCF

14.1 28.3 29.2 38.9 59.9 80.0

HCF HCF + + UV

18.1 30.5 30.6 41.6 58.2 78.1

HCF HCF + + ESP

79.9 98.7 98.11 82.5 96.1 100

HCF HCF + + Do Double E ESP

88.1 98.2 97.29 82.9 100 100

HCF HCF + ESP + A AC

86.8 98.4 97.62 94.3 100 100

Xia Zhong (University of Sydney), Sven Bolomey (AOM Australia), Commercial kitchen exhaust contaminant removal using combined treatment techniques and filtration efficiency assessment with developing standardised testing protocol, AIRAH Presentation Future of HVAC 2018

51

Filtration System Design

Beware of standardised equipment supplier specifications not necessarily adapted to commercial kitchen exhaust.

USEPA Method 5 Dete terminati tion of

• f Particulate Matte

tter Emissi ssions ns fro rom Stationary Sourc rces ASHRAE 52.2-2017 Method of

• f T

Tes estin ing G General l Ventila lation A Air-Clea eaning D Devi evices es for Removal E Efficien ency by by Particle S e Size ASTM F1605-95 Standa ndard Te Test Met ethod for Perfo formance of

• f Doubl

ble-si sided ed Grid iddle les

No c curren ent te t testing p protocol a adapted ed to to commer ercial k kitchen en e exhaust

52

Filtration System Design

VOCs removal assessment

To Total VOCs Cs remova val AC 89% 89% vs

• vs. Ozo

zone 92% 92%

• Research testing showed that both
• zone injection and activated carbon

have a significant impact on VOCs, that compose odour.

• This is in line with independent

testing carried out on specific projects.

53

Filtration System Design

Beware of the rise of the Ali Baba filtration system – no after sales, no servicing, no performance certification

54

Filtration System Design

A well designed Filtration System is only as good as the maintenance of the system

• Maintenance of filtration systems come at a cost which should be

included into design phase Cost Estimates.

• Cost should include additional parts and labour.
• Certain suppliers can provide an upfront estimate / fixed quote for

first year of servicing with added advantages such as warranty extensions, bank of spare filters, etc. Movement towards remote monitoring of Filtration Plants as

• pposed to current fixed maintenance regimes as well as increased

accessibility of Autowash systems.

55

Filtration System Design

Particle Matter Filtration - Major conclusions

• PM discharges from commercial kitchen exhaust are significant and can significantly

contribute to urban air pollution.

• Concentration of contaminants depend on the cooking equipment used.
• Electrostatic precipitators are the best adapted equipment for high efficiency filtration of

commercial kitchen exhaust.

• UV treatment showed no significant impact to particle removal – further testing is

required to understand the impact of UV treatment.

AS1668.2-2012 calls for a reduction of contamination

56

Filtration System Design

Odour Mitigation - Major conclusions

• Odour composition is complex, forming different types of sensorial impacts.
• Testing showed that both ozone injection and activated carbon have a significant impact
• n VOCs that compose odour.
• However, odour is a sensorial attribute that differs between people. Current sensorial

testing is complex to implement and does not allow for monitoring (AC efficiencies decrease significantly over time).

• Need to better link sensorial and chemical testing protocols.

AS1668.2-2012 states that odour mitigation is the key parameter to designing a non compliant discharge point.

Exhaust hood design

With a multitude of different issues

57

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Exhaust hood design

AS1668.2-2012 Constraints to hood design (Appendix E)

58

• E3.4.1 Sloping All surfaces of the hoods exposed to the appliance being ventilated shall be sloped at an angle not

greater than 40 degrees from the vertical, unless the design and performance of the hoods prevent the formation of condensate on such surfaces.

• Minimum hood heights when designing

hoods based on standards are:

• Hood over woks or ovens: 920 mm
• Hood over grills, stove, etc: 700 mm

Exhaust hood design

Hood Type 7 Proprietary Equipment

59

Exhaust hood design

Example of Proprietary Hood airflow calculations that significantly reduce the exhaust requirements.

60

• Standard hood calculation method for Type 4

cooking: Hood 2: 375 x 1.2 x (4.3+4.3+2.3+2.3) = 6,120 l/s

No. Cooking Process Type Hood Type Dimensions (mm) Exhaust Air Flow Rate (L/s) Make up Air Flow Rate (L/s) 1 5 – High Grease / High Heat 4 – Island 4,850 x 2,700 6,795 6,150 2 4 – High Grease /

• Med. Heat

4 – Island 4,400 x 2,400 6,120 5,600 3 4 – High Grease /

• Med. Heat

4 – Island 4,400 x 2,700 6,390 5,750 4 4 – High Grease /

• Med. Heat

4 – Island 4,400 x 2,700 6,390 5,750 5 3 – High Grease / Low Heat 3 – Sidewall 4,400 x 1,350(1500) 1,620 1,490 6 4 – High Grease /

• Med. Heat

4 – Island 7,800 x 1,900 8,730 7,900

• Standard hood calculation method for Type 2 and

Type 4 cooking: Hood 2: Type 4: 375 x 1.2 x (4.3+1.15+1.15) = 2,970 l/s Type 2: 190 x 1.2 x (4.3+1.15+1.15) = 1,500 l/s Total: 4,470 l/s

Exhaust hood design

Example of Proprietary Hood airflow calculations that significantly reduce the exhaust requirements – yet consider condensation risk of the given equipment

61

• a. Vth final

Exhaust hood design

Example of Proprietary Hood airflow calculations that DO NOT reduce the exhaust requirements – BECAUSE the calculations considers condensation risk of the given equipment

62

• Specified hood dimensions: 9000 (l) x 1650 (w) x 600 (h) mm
• Type 3 cooking: 190 x 1.1 x (8.9+1.55+1.55) = 2,300 l/s

Note: height of the hood is not feasible with a standard hood

Exhaust hood design

Example of Proprietary Hood airflow calculations that DO NOT reduce the exhaust requirements – BECAUSE the calculations considers condensation risk of the given equipment

63

• a. Vth final

Exhaust hood design

Advantages to Performance Hoods

64

• More flexibility in the design (dimensions) of the exhaust hood.
• Integrated Make Up Air systems which improve capture of exhaust and facilitate overall

balancing of kitchen space.

• Higher quality finishing including LED lights, high efficiency in hood grease filters.
• In light of their design, generally allow for additional filtration to be located within the exhaust

hood: UV systems, Electrostatic Precipitators.

• Better management of exhaust airflows with overall tendency being a decrease in exhaust rates.

However the exhaust hoods need to prove performance to a tested standard and clearly be able to justify specified exhaust rates – otherwise, they are simply an expensive box.

Balancing kitchen space

Creating a perfect commercial kitchen working space

65

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Balancing kitchen space

General Make Up Air Strategies

66

• Minimise the exhaust requirements.
• Standard practice - 80% of the exhaust air value to be replaced within the

kitchen space

• In or close to the exhaust hood: 60%
• A/C of kitchen space: 20%
• Transfer air: Balance of 20%
• Displacement ventilation systems as opposed to mixing ventilation to be

used in the vicinity of the exhaust hood.

• Increased use of Transfer Air (up to 50%) in order to recycle used

conditioned air as MUA, thus also improving the working conditions in the kitchen.

Balancing kitchen space

In hood MUA solutions: methods with limited scope

67

• Replacement air introduced directly into the

hood cavity of kitchen exhaust hoods shall not exceed 10% of the hood exhaust airflow rate.

• Air curtain is a “risky design option” and it is

recommended limiting the percentage to a maximum of 20% of MUA.

Balancing kitchen space

In hood MUA solutions

68

• It is vital that front face MUA be limited in velocity, be

provided in a horizontal direction and be delivered uniformly through the front face of the hood.

• Potential for up to 80% of MUA.

Balancing kitchen space

Displacement diffusers

69

• Supplying make up air through displacement diffuser at a

good distance away from the hood.

• Similar to low velocity “transfer air” from the dining room
• Diffusers require floor /wall space which is difficult in a

commercial kitchen.

• Terminal velocity and edge of the hood capture area

should not exceed 0.25 m/s

Fan Design

Where Commercial Kitchen Ventilation Design can work towards Energy Efficiency

70

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Fan Design

Demand Control Kitchen Ventilation

71

If a kitchen/dining facility has a total kitchen hood exhaust airflow rate greater than 5,000 cfm then it shall have one of the following: a) At least 50% of all replacement air is transfer air that would

• therwise be exhausted.

b) Demand ventilation system(s) on at least 75% of the exhaust air. Such systems shall be capable of at least 50% reduction in exhaust and replacement air system airflow rates(…)

Fan Design

Demand ventilation system(s) – Can achieve up to 50% Energy Savings

72

http://www.wbdg.org/FFC/ARMYCOE/TECHNOTE/technote21.pdf

• Manual system with a single-

phase 2-speed motor (high or low)

• Automated system with a single-

phase 2-speed motor (high or low)

• Control System for 3-phase

motors with variable speed (temperature sensors)

• Advanced Control System

(temperature and optic sensors)

Ducting Design

Main elements allowing for demand ventilation systems

73

• 1. Discha

harge po point ide dentif ificatio ion

• 2. Cookin

ing T Type pe cons nstrain ints

• 4. Exha

haust ho hood des esign

• 3. Fi

Filtratio ion s system des esign

• 7. Duc

ucting ing de design

• 6. F

Fan de n design

• 5. Balancing

ing k kitche hen n spa pace

Ducting Design

Maximum Velocity through ducting

74

• Horizontal ducting generally designed to around

7.5 m/s velocity.

• NFPA 96 Code changed to 2.54 m/s as minimum

design velocity – allowing for Demand Control Ventilation

• Three key actions to grease deposition in ducts.
• 1. Gravitational settling
• 2. Turbulent deposition
• 3. Thermophoresis

75

Final Thoughts - From Design to Supply / Install to Maintenance

Designing and Installing a performant Commercial Kitchen Ventilation System requires that all different elements are fully integrated.

• Decreasing local impacts:
• A well designed discharge point is a function of airflow (exhaust hood), cooking type and

implemented filtration equipment.

• Optimising system performance:
• A well balanced and energy efficient commercial kitchen is a function of exhaust hood

performance in a well balanced space and fan selection / duct design.

• Decreasing risk:
• A system that decreases grease accumulation and allows for effective maintenance is a

function of exhaust hood, specified filtration systems and duct design.

Full system design should be undertaken by the Mechanical Engineer and Supplied / Commissioned by the Mechanical Contractor.

Thank You

Sven Bolomey 1300 300 9 903 03 7 788 88 design@ao aomau aus.com www.aomaus.com.au

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