XLT Ovens, Eyebrow Hood and Model 3255-TS3 Gas Conveyor Pizza Oven
Capture and Containment Performance Tests
Application of ASTM Standard Test Method F 1704-05
FSTC Report 5011.09.05
Food Service Technology Center July 2009
Prepared by: Rich Swierczyna
Paul Sobiski Architectural Energy Corporation
Prepared for: Pacific Gas & Electric Company
Customer Energy Efficiency Programs P.O. Box 770000
San Francisco, California 94177
2009 by Fisher-Nickel Inc. All rights reserved.
The information in this report is based on data generated at the PG&E Food Service Technology Center
its affiliated Commercial Kitchen Ventilation Laboratory (CKVL)
Acknowledgments
California consumers are not obligated to purchase any full service or
other service not funded by this program. This program is funded by
California utility ratepayers under the auspices of the California Public
Utilities Commission.
Los consumidores en California no estan obligados a comprar servicios completos o adi-
cionales que no esten cubiertos bajo este programa. Este programa esta financiado por los
usuarios de servicios públicos en California bajo la jurisdiccion de la Comision de Servicios
Públicos de California.
A National Advisory Group provides guidance to the Food Service
Technology Center Project. Members include:
Applebee’s International Group
California Energy Commission (CEC)
Denny’s Corporation
East Bay Municipal Utility District
Enbridge Gas Distribution Inc.
EPA Energy Star
Gas Technology Institute (GTI)
In-N-Out Burger
National Restaurant Association
Safeway, Inc.
Southern California Edison
Underwriters Laboratories (UL)
University of California at Berkeley
University of California at Riverside
US Department of Energy, FEMP
Specific appreciation is extended to XLT Ovens for supplying the gas conveyor pizza oven for controlled testing at the CKV Laboratory.
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• Fisher-Nickel, inc. and the Food Service Technology Center
(FSTC) do not endorse particular products or services from any
specific manufacturer or service provider.
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using the best available scientific techniques and instrumentation.
• The FSTC is neutral as to fuel and energy source. It does not, in
any way, encourage or promote the use of any fuel or energy
source nor does it endorse any of the equipment tested at the
FSTC.
• FSTC test results are made available to the general public through
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• In the event that FSTC data are to be reported, quoted, or referred
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Food Service Technology Center. In any such publication, sufficient
text must be excerpted or quoted so as to give full and fair repre-
sentation of findings as reported in the original documentation from
FSTC.
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This report was prepared as a result of work sponsored by the California Public Utilities Commission (Commission). It does not necessarily repre-sent the views of the Commission, its employees, or the State of Califor-nia. The Commission, the State of California, its employees, contractors, and subcontractors make no warranty, express or implied, and assume no legal liability for the information in this report; nor does any party rep-resent that the use of this information will not infringe upon privately owned rights. This report has not been approved or disapproved by the Commission nor has the Commission passed upon the accuracy or ade-quacy of the information in this report.
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Neither Fisher-Nickel, inc. nor the Food Service Technology Center nor any of its employees makes any warranty, expressed or implied, or as-sumes any legal liability of responsibility for the accuracy, completeness, or usefulness of any data, information, method, product or process dis-closes in this document, or represents that its use will not infringe any privately-owned rights, including but not limited to, patents, trademarks, or copyrights. Reference to specific products or manufacturers is not an endorsement of that product or manufacturer by Fisher-Nickel, inc., the Food Service Technology Center or Pacific Gas & Electric Company (PG&E). Retention of this consulting firm by PG&E to develop this report does not constitute endorsement by PG&E for any work performed other than that specified in the scope of this project.
Contents
DRAFT 5011.09.05 i
Food Service Technology Center
Page
1-1 XLT Ovens 3255-TS3 ........................................................... 1-3
1-2 XLT Ovens Close-Coupled Eyebrow Hood ........................... 1-4
1-3 Baffle Filter for Exhaust Hood ............................................... 1-4
2-1 Laboratory Layout .................................................................. 2-1
2-2 Equipment Layout .................................................................. 2-4
2-3 Schlieren Visualization Image at Spill Condition .................... 2-5
2-4 Schlieren Visualization Image at C&C Condition.................... 2-5
Page
1-1 Appliance Specifications ....................................................... 1-3
1-2 Hood Specifications ............................................................... 1-4
3-1 Summary of Capture and Containment Performance ............ 3-2
Page
1 Introduction ................................................................................. 1-1
Background ............................................................................ 1-1
Objectives ............................................................................... 1-2
Appliance Description ............................................................. 1-3
Hood Description .................................................................... 1-4
2 Methods ....................................................................................... 2-1
Airflow Visualization ............................................................... 2-1
Capture and Containment Testing ......................................... 2-2
Setup and Instrumentation ..................................................... 2-3
3 Results ......................................................................................... 3-1
Capture and Containment Testing ......................................... 3-1
4 Conclusions ................................................................................. 4-1
5 References ................................................................................... 5-1
Appendix A: Appliance Specifications
Appendix B: Hood Specifications
Figures
Tables
1 Introduction
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Conveyor pizza ovens allow for the rapid cooking of food products with
consistency and ease of operator use. They generally have a large kitchen
footprint, a high-input gas burner or electric elements, and a high volume
capacity to cook the food at a very high rate. The importance of considering
the required ventilation rate as well as the energy input and efficiency for
such a powerful appliance cannot be understated.
Dedicated to the advancement of the food service industry, the Food Service
Technology Center (FSTC) has focused on the development of standard test
methods for commercial food service equipment since 1987. The primary
component of the FSTC is a 10,000 square-foot appliance laboratory
equipped with energy monitoring and data acquisition hardware, 60 linear
feet of canopy exhaust hoods integrated with utility distribution systems,
appliance setup and storage areas, and a state-of-the-art demonstration and
training facility.
Likewise, the Commercial Kitchen Ventilation Laboratory (CKV Lab) has
been dedicated to the improvement of kitchen ventilation since the early
1980’s. The test cell at the CKV Lab is a 900 square foot airtight room,
equipped with similar energy metrology. In addition, two schlieren and two
flow visualization systems are available to verify proper hood capture and
containment performance and provide evaluation of hood and appliance
modifications in real-time.
The hand-in-hand teamwork of the two facilities has provided the commer-
cial kitchen industry with information regarding the hood and appliance sys-
tems that has been the foundation for codes, standards, ASHRAE Hand-
books, and helped drive energy conservation with regards to commercial
kitchens.
Background
Introduction
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The test methods, approved and ratified by the American Society for Testing
and Materials (ASTM), allow benchmarking of equipment such that users
can make meaningful comparisons among available equipment choices. End-
use customers and commercial appliance manufacturers consider the FSTC
to be the national leader in commercial food service equipment testing and
standards, sparking alliances with several major chain customers to date.
The performance of a hood and appliance system is not only characterized
by preheat time, energy profile, and production capacity, but also by the ex-
haust airflow rate needed to capture and contain the thermal and cooking
plumes generated by the appliance during idle and cooking conditions.
The XLT Ovens 3255-TS3 conveyor pizza oven features a stackable design.
This design provides the end user with the option to purchase the appliance
in a one, two or three deck configuration and each deck operates independ-
ently. The oven was tested under an XLT Ovens designed close-coupled
eyebrow hood. The hood and appliance was tailored as a system by XLT
Ovens by careful integration of panels and food take-away shelves while
maintaining ease of use by personnel.
The objective of this report is to examine capture and containment perform-
ance of XLT Ovens 3255-TS3 conveyor pizza oven and close-coupled eye-
brow hood system under the controlled conditions of ASTM standard test
method F1704-05, Capture and Containment Performance of Commercial
Kitchen Exhaust Ventilation Systems. The scope of testing included:
1. Determining the exhaust rates required for one, two and three-
deck operation in a baseline configuration.
2. Determining the change in required exhaust rate for appliance
operation without the integrated panels.
3. Determining any capture and containment performance im-
provements to be had with minor alterations, such as adding
holes to the food take-away trays.
Objectives
Introduction
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XLT Ovens’ 3255-TS3 conveyor pizza oven is a stackable unit and was
tested in the triple deck configuration. The oven is equipped with an 88-inch
long by 32-inch wide variable speed conveyor, which passes through a 55-
inch long high-velocity impingement bake zone using a natural gas burner
rated at 150,000 Btu/h per deck and a 120 VAC electrical input rated at 6
amps per deck. The oven is of stainless steel construction and features a
solid-state control panel for temperature and conveyor speed adjustments.
Appliance specifications are listed in Table 1-1, an image of the appliance is
shown in Figure 1-1, and the manufacturer’s literature is in Appendix A.
Table 1-1. Appliance Specifications.
Manufacturer XLT Ovens
Model 3255-TS3
Generic Appliance Type Conveyor Pizza Oven
Rated Gas Input 150,000 Btu/h (per deck)
Rated Electrical Input 6 amps @ 120 VAC
Cooking Area 32″ x 55″
Controls Solid State
Construction Stainless Steel
Appliance Description
Figure 1-1.
XLT Ovens’ 3255-TS3.
Introduction
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The hood used for testing was an XLT Ovens close-coupled eyebrow hood,
which had overall dimensions of 111.5 inches long, 48.3 inches deep, and 20
inches tall. It had two 2.7 foot filter banks, each with a 15.5-inch high by
19.5-inch wide baffle filter located directly over the entrance and exit of the
oven. Each filter bank had a 16-inch wide by 8-inch tall duct which con-
nected to a 12-inch by 12-inch exhaust collar. A summary of the hood speci-
fications is presented in Table 1-2, an image of the hood is shown in Figure
1-2, and an image of the filter used in the hood is shown in Figure 1-3.
Table 1-2. Hood Specifications.
Manufacturer XLT Ovens
Model Prototype
Generic Hood Type Eyebrow Hood
Length 111.5 inches
Depth 48.3 inches
Height 20.0 inches
Filtration Two Baffle Filters, 15.5 inches x 19.5 inches each
Exhaust Collar 12.0 inches x 12.0 inches
Hood Description
Figure 1-2.
XLT Ovens’
Close-Coupled
Eyebrow Hood
Figure 1-3.
Baffle Filter
2 Methods
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The primary tools used for airflow visualization were schlieren and shadow-
graph systems, which visualize the refraction of light due to air density
changes. Since the hot air and effluent generated by the cooking process
change the air density around the equipment, the sensitive flow visualization
systems provide a graphic image of the thermal activity along the perimeter
of the hood. The left and right lower edges of the hood were monitored by
schlieren systems located at a height that was between the typical 36-inch
appliance height and the 78-inch hood height. The front lower edge of the
hood was monitored using a shadowgraph system, located at the same height
as the hood edge or adjusted to be in line with the oven deck being evalu-
ated. Other flow visualization tools used to seed the thermal plume included
small smoke sticks. Figure 2-1 shows a plan view of the laboratory with the
relative position of the hood and flow visualization tools.
6'-9"
11'-6"
19'-10"
9.3 ft x 4.0 ft x 1.7 ft
Eyebrow HoodOptics Box
Schlieren
5'-5 1/2"
PiezometerRing
Supply Diffuser Wall
Shadow
gra
ph
Shadow
gra
ph
Optics Box
Schlieren
Hood Collar
Supply Diffuser Wall
Airflow Visualization
Figure 2-1.
Laboratory Layout.
Methods
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"Hood capture and containment" is defined in ASTM F1704-05 [Ref 1],
Capture and containment performance of commercial kitchen exhaust venti-
lation systems, as "the ability of the hood to capture and contain grease laden
cooking vapors, convective heat and other products of cooking processes”.
Hood capture refers to the products getting into the hood reservoir, while
containment refers to these products staying in the hood reservoir and not
spilling out into the space. "Minimum capture and containment" is defined
as "the conditions of hood operation at which the exhaust flow rate is just
sufficient to capture and contain the products generated by the appliance in
idle and heavy load cooking conditions, or at any intermediate prescribed
load condition."
For each capture and containment (C&C) evaluation, the exhaust rate was
reduced until spillage of the plume was observed along the perimeter of the
hood using airflow visualization techniques described in the previous sec-
tion. The exhaust rate was then increased in fine increments until capture
and containment was achieved. For most cases, single-test determinations
were used to establish the airflow rate for threshold capture and contain-
ment. The airflow measurements in the laboratory comply with the AMCA
210/ASHRAE 51 Standard [Ref 2]. The error on the airflow rate measure-
ment is less than 2%. The repeatability of capture and containment determi-
nations is typically within 5%.
Capture and Containment Testing
Methods
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The XLT Ovens 3255-TS3 was installed under the XLT Ovens close-
coupled eyebrow hood. The appliance operation was varied to evaluate ven-
tilation rates for one, two, and three deck operation. Operation was usually at
idle conditions, with some cooking conditions included to evaluate sensitiv-
ity. The configuration of the system was modified to evaluate the effective-
ness of the panels and the food take-away trays. During the performance
evaluation, schlieren flow visualization systems were used to ensure proper
effluent capture and containment and were augmented by shadowgraph and
smoke visualization. A photograph of the typical test setup of the triple deck
oven, eyebrow hood, and integrated panels is shown in Figure 2-2, and a
photograph illustrating schlieren visualization is shown in Figure 2-3.
The oven was calibrated and operated during the hood performance testing
according to ASTM F1817 Standard Test Method for the Performance of
Conveyor Ovens [Ref 3], except where noted. The standard required a cali-
brated oven cavity temperature of 475°F, which was achieved using a 465°F
setpoint. If cooking, capture and containment performance was determined
while baking plain 12-inch cheese pizzas under heavy-load conditions, which
maximizes the coverage of the conveyor with pizza.
Exhaust static pressure was measured using four pitot-static pressure sensors
connected to a piezometer ring located in a 16.75 inches by 16.50 inches rec-
tangular section of the exhaust duct. The peizometer ring was located 15
inches downstream from the boot used to transition between the rectangular
duct and 12 inch round ductwork connected to the hood collar.
Setup and Instrumentation
Methods
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Figure 2-2.
Equipment configuration.
Methods
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Figure 2-3.
Schlieren visualization during spill condition at 400 cfm with three decks in operation.
Figure 2-4.
Schlieren visualization during C&C condition at 1200 cfm with three decks in operation.
3 Results
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At idle conditions, 200, 700, and 1100 cfm was documented for the best cas-
es of one, two, and three deck operation, respectively. By switching off
decks as demand allowed, a reduction of up to 82% was possible if the top
deck was in operation rather than all three decks.
The panels significantly reduced the required exhaust rate for proper capture
and containment. Two-deck operation required 700 cfm at idle conditions.
For comparison, operation without the integrated panels required 2400 cfm
during two-deck operation. Therefore, the panels provided a reduction of
1700 cfm, or 71%, for two-deck operation.
For two testing scenarios, modification or removal of the take-away trays
was evaluated and shown to be beneficial. This modification provided up to
a 100 cfm reduction, or 13%. The capture and containment test results are
summarized in Table 3-1.
Capture and Containment Testing
Results
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Table 3-1. Summary of Capture and Containment Performance During Idle Conditions at
465°F Setpoint (unless otherwise noted).
Number of
Decks
C&C
Rate
[cfm]
Exhaust Static
Pressure
[in. of water]
Panel
Configuration
Tray
Configuration
1 Deck 200 0.01 End load,
end discharge Load w/o trays,
discharge with holes in trays
1 Deck a 400 0.04 End load,
end discharge Load w/o trays,
discharge with holes in trays
2 Deck 700 0.12 End load,
end discharge Without trays
2 Deck 800 0.16 End load,
end discharge With solid trays
2 Deck b 800 0.16 Side load,
end discharge With solid trays
2 Deck 800 0.16 Side load,
end discharge With solid trays
2 Deck 2400 2.70 Without panels Without trays
3 Deck 1100 0.42 Side load,
end discharge With holes in trays
3 Deck 1200 0.55 Side load,
end discharge With solid trays
3 Deck 1200 0.55 End load,
end discharge Load w/o trays,
discharge with holes in trays
3 Deck 1200 0.55 End load,
end discharge Load w/o trays,
discharge with solid trays
3 Deck 1200 0.55 End load,
end discharge Without trays a 465°F setpoint, cooking conditions.
b 540°F setpoint, idle conditions.
4 Conclusions
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XLT Ovens’ 3255-TS3 conveyor pizza oven and hood system performed
well under the rigorous conditions of the ASTM F1704-05 Standard Test
Method for the Capture and Containment Performance of Commercial
Kitchen Exhaust Ventilation Systems. When optimized with integrated panels
and improved food take-away trays, the required ventilation rate was as low
as 200 cfm for the top deck operation. With all three decks in operation, the
required exhaust rate was 1100 cfm.
The optimization of the hood and appliance as a system significantly reduced
the required exhaust rate. Without the optimization of integral panels, 2400
cfm was needed for proper ventilation of two deck operation. With the pan-
els installed and the food take-away trays removed, the exhaust rate was re-
duced to 700 cfm, which is a reduction of 1700 cfm, or 71%. The combina-
tion of an excellent conveyor pizza oven, close-coupled eyebrow hood, and
carefully engineered integration of the two devices has resulted in an effi-
cient system that can deliver a high quantity of pizza while operating with a
very low quantity of exhaust.
5 References
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1. ASTM 2005. ASTM Designation F1704-05, Capture and Containment Performance of Commercial
Kitchen Exhaust Ventilation Systems. West Conshohocken, PA.
2. Air Movement and Control Association, Inc. and American Society of Heating, Refrigeration, and Air
Conditioning Engineers, Inc. Laboratory methods of testing fans for rating. AMCA Standard
210/ASHRAE Standard 51, Arlington Heights, IL and Atlanta, GA.
3. American Society for Testing and Materials. 2007. Standard Test Method for the Performance of Con-
veyor Ovens. ASTM Designation F 1817-03, in Annual Book of ASTM Standards, West Conshohocken,
PA.
A Appliance Specifications
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Appendix A includes the product literature for the XLT Ovens 3255-TS3
conveyor pizza oven.
Table A-1. Appliance Specifications.
Manufacturer XLT Ovens
Model 3255-TS3
Generic Appliance Type Conveyor Pizza Oven
Rated Gas Input 150,000 Btu/h
Rated Electrical Input 6 amps @ 120 VAC
Cooking Area 32″ x 55″
Controls Solid State
Construction Stainless Steel
A Appliance Specifications
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A Appliance Specifications
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A Appliance Specifications
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A Appliance Specifications
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B Hood Specifications
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