Technical

Technical Information

Specifications are subject to change due to continuing engineering improvements and legislative changes. You are urged to contact us for current specifications prior to using this information in your projects.

The use of gas backup or full gas installations can have many benefits, such as staffing (reduced attendance during off-peak periods), logistics (keeping up a continuous supply of firewood fuel, or a breakdown in deliveries), shorter heating times from cold, or simply the advantages of a Beech oven where wood supply is scarce or the use of wood is prohibited by regulations.

Approvals / Compliance

CE rating Europe. The gas equipment used in Beech stone hearth ovens adheres to all CE directive requirements.
UK Smoke Free Zone Exemption. The full range of Beech Ovens can be used anywhere in the UK.
UL/EPH Rating USA. Please contact us for the separate sheets for UL listed products.

bbs015 (Feb 2003)

OVEN TYPE	GAS BACKUP	GAS BACKUP	GAS BACKUP	GAS ONLY *	NO GAS
GAS TYPE	NATURAL	LPG	TOWN GAS	ALL GASES	WOOD ONLY
Thermal Input	80 MJ/Hr	80 MJ/Hr	80 MJ/Hr	160 MJ/Hr	N/A
	76,000BTU	76,000BTU	76,000BTU	152,000BTU	N/A
Gas Supply Line	19mm Cu	19mm Cu	19mm Cu	2 x 19mm Cu	N/A
	3/4"	3/4"	3/4"	2 x 3/4"	N/A
Power supply - Outside USA	240 v 10A	240 v 10A	240v 10A	240V 10A	N/A
Power supply - Mainland USA	110V 10A	110V 10A	110V 10A	110V 10A	N/A
Burner Jet Size	4.1mm Diam	2.30mm Diam	5.6mm Diam	Same	N/A
	Drill #20	Drill #43	Drill #2	Same	N/A
Gas pressure at burner injector	1KPA	2.75KPA	0.6KPA	Same	N/A
Gas pressure at burner injector	4"WC	11" WC	2.4" WC	Same	N/A
Gas supply pressure to inlet at isolating valve kPA	7.0kPA MAX	7.0kPA MAX	7.0kPA MAX	Same	N/A
Gas supply pressure to inlet at isolating valve kPA	2kPA MIN	3.0kPA MIN	0.7kPA MIN	Same	N/A
Gas Supply Pressure to Inlet at Isolating Valve PSI	1 PSI MAX	1 PSI MAX	1 PSI MAX	Same	N/A
Gas Supply Pressure to Inlet at Isolating Valve PSI	0.3 PSI , MIN	0.45 PSI MIN	0.1 PSI MIN	Same	N/A
Gas Consumption per Hour (Approx)	2.0 M3/Hr	0.6 M3/Hr	3.9 M3/Hr	Double	N/A
Gas Consumption per Hour (Approx)	72 Ft3 / Hr	22 Ft3/ Hr	130Ft3/Hr	Double	N/A
Timber Consumption Hard Wood	0.1 M3 Per Day	0.1 M3 Per Day	0.1 M3 Per Day	N/A	0.2 M3 per 12 hour day
Timber Consumption Hard Wood	3 CU Ft	3 CU Ft	3 CU Ft	Same	6 CU Ft per 12 hour day
Duct size- Natural draft (or equivalent round)	400mm SQ	400mm SQ	400mm SQ	Same	400mm SQ
Duct size- Natural draft (or equivalent round)	16" SQ	16" SQ	16" SQ	Same	16" SQ
Duct size- Fan assisted (or equivalent round)	300mm SQ	300mm SQ	300mm SQ	Same	300mm SQ
Duct size- Fan assisted (or equivalent round)	12" SQ	12" SQ	12" SQ	Same	12" SQ
AIRFLOW REQUIRED (ALL FUELS)	Single mouth oven; Min 700 Litres/Sec (1500Cfm); no maximum as suction is controlled by flue damper. Oven with grill; Min 1000 Litres/Sec (2000Cfm); no maximum as suction is controlled by flue damper.
Secondary Air for Gas Burner	6.0 litres per second (approx)	6.0 litres per second (approx)	6.0 litres per second (approx)	12.0 litres per second (approx)	N/A
	12 cfm approx	12 cfm approx	12 cfm approx	24 cfm approx
Air Conditioning Heat Load	Less than 2 Kw Heat Load (7000 Btu)

Note:
• Metric / Imperial conversions are close approximations and not necessarily exact.
• The term "same" or "double" in the "Gas only" ovens column means the same, or double, the specification for the type of gas in use, e.g. natural gas, LPG or Town gas.

Venting Requirements

Dwg 510 (55kb)
Dwg 221 (33kb)
Beech Canopy Venting (112kb)
Beech Exhaust Options (3.46mb)

Exhaust Duct Design

1. Introduction

Refer to Dwg 510 and Dwg 221. All Beech Stone Hearth Ovens require ductwork by others. To facilitate easy connection to the oven, Beech sell optional transition ducts, damper assemblies and Spray Filters. This section refers to the correct selection and use of these accessories and the needs of the ductwork design by others. To ensure long term safe operation of your oven it is critical that the following flue design guidelines are followed.

The exhaust should be built according to local health and fire department codes for your city / county / state and should be installed by a qualified ventilation contractor. (In Australia this code is as1668.) This information should be used as a guide only and does not override local regulations.

2. General

Minumum Flue Material Requirements: 1.2 mm Galv Sheet Metal or 0.9 SS.
Preferred Flue Material: Double skinned insulated, fire resistant type stainless steel flue pipe available from proprietary manufacturers and local fabrication workshops.
Recommended Flue Size: 300mm sq or equivalent with exhaust fan.
Nominal Airflow Required: Min 700 litres/ second (l/s) (1500cfm) for 1 door ovens. Add 100 litres /second for all each additional door in the oven. The duct can be connected to an existing kitchen exhaust system with a much higher flow rate by controlling the suction utilising a damper fitted by the mechanical contractor.
A damper must always be provided by the installing contractor.
Ovens can be fitted by direct connect or beneath an approved canopy system.
Electrical Cabling must NEVER be laid across ductwork.
Access must be available to above and below the oven.
Any voids above and below the oven must be vented.
Transition ducts and spray filters supplied by Beech always come with a cool air relief valve to reduce duct gas temperatures.

3. Flue Fire Prevention

Flue fires occur when the ductwork is not regularly cleaned (see Section 5) below. The threat of fire can be reduced by the addition of:

A 180-degree Celsius sprinkler head within the ductwork located after the cool air inlet.
An Ansul or similar automatic fire suppression head located within the ductwork located least 1 metre from the mouth of the oven.
A Beech Spray Filter.

4. Oven Performance

The performance of a Stone Hearth Ovens will be affected by:

Too much suction – control this with damper by others.
The effect of strong winds
Kitchen static pressure imbalance.
A prefiring calibration video is also available.

5. Ductwork Cleaning

NOTE: The by-products of burning wood and cooking fatty foods (cheese and meat) all lead to a highly flammable residue buildup in the duct. The duct MUST be cleaned every three months or at intervals determined by an approved experienced duct cleaner.

Ductwork must be kept 100mm away from combustible material ie timber work in ceiling. If this is not possible ensure a recognised fireproof insulation is securely placed between metal duct and combustible material.
Clean out access openings required to complete length of ductwork.

6. Australian Gas Rules Specify:

Flue Design Option 1 (Non Mechanically vented) is not allowed with a gas backup system.
In Options 2 & 3, there must be an interlock provided between the fan and the gas system to ensure gas shutdown if the fan fails to run.

7. Flue Design Options

Ductwork Selection Table

	Option 1	Option 2 Communal Duct	Option 2 Dedicated Duct	Option 3 Communal Duct*	Option 3 Dedicated Duct*
Wood Only	OK	NO	OK	OK	OK
Gas Only	NO**	OK	OK	OK	OK
Gas & Wood	NO**	NO	OK	OK	OK

Note:
* A correctly installed and maintained spray filter enables safe connection of a solid fuel oven to ductwork. Appropriate routine maintenance /inspection of the spray assembly and ductwork is still essential to ensure the self-cleaning apparatus is functioning correctly to clean the ductwork. Refer to Operational manual and Clause 1 above for details. NOTE: Local Health /Fire Departments Codes may not allow connection of a solid fuel burning oven to communal ductwork even with the Beech Spray Filter. Contact Beech Ovens for further assistance in ductwork approval.
** Refer to Clause 6.0 Flue Design above.

Option 1 - Natural Thermal Draft - Single / Two Story Blds - No Fan
Dedicated flue less than 15m in length with less than 5m horizontal, eg in a simple single level building. Flue size 300 x 300. No fan required. Use a weatherproof vertical discharge capable of minimising effect of wind. (See also Clause 1 and Clause 4).
Option 2 - Mechanically Ventilated – Direct Connection To Oven Or Canopy - No Sprayfilter, Suitable For Shopping Centres/ High Rise Blds
Refer to all clauses above.
Suitable for Full Gas Ovens as there is much less residue buildup. Only suitable for solid fuel burning ovens when combined with a regular duct-cleaning program. See Specifically Clause 3 & Clause 5 above.
Option 3 - Using Beech Water Spray Filter System - Mechanically Ventilated – Direct Connection To Oven Suitable For Shopping Centres/ High Rise Blds
This design utilises a water misting spray inside the ductwork to remove soot, grease and heat. It enables safe connection to any existing ductwork. The impurities are drained to waste with the spray water. Refer Dwg 510 Option3 and Dwg 221. The advantage of this system, especially when burning solid fuel, is that the system is self cleaning. Note *7 above.
Option 4 - OVERHEAD CANOPY
An appropriately size canopy can be used to exhaust the oven. Refer to the Beech Canopy Venting.

How To...

Measure Oven Performance

Maintain an Oven

For all Beech ovens, day to day operation involves a simple routine that ensures a full day of trouble free, efficient cooking in a very powerful oven. For each type of oven, 'wood only', 'gas backup' (wood and gas) and 'full gas', there is a simple routine that can be performed each morning to ensure 'hi-performance' cooking for the rest of the day.

There is a need to start the oven warm up period at least one hour before cooking is required to commence. Each oven contains a large amount of refractory material which is the Thermal Mass of the oven, providing the high performance that is synonymous with Beech Ovens.

From time to time it is recommended to bring the oven temperature to 400°C (752°F) (over-fired) for an hour or so to fully clean the oven of food stuffs and debris. This is best done when the oven is not to be used for a few hours, as it takes a few hours to cool down to optimum cooking temperature afterwards. This simple task can be done every week on two. (Do not use water to clean the oven.)

Good performance is dependent on initial set-up of the gas system (where applicable) and the flue calibration. This work is done during installation and commissioning as outlined in the Pre Fire Checklist. Once set up correctly there are no more adjustments to be made. It is advisable to check the operation specifications of these functions periodically to maintain peak performance. Beech Ovens recommend regular flue inspections and clean-outs as required. This is a good time to check flue calibration and make any adjustments necessary.

If your oven is not performing to expectations, it may be that the flue calibration has not been correctly set during commissioning of the oven. Please review the installation manual and commissioning CD provided with the oven to correct the problem, or contact us for additional support.

Daily Operation, Wood Only Oven

Each morning the ash from the previous day's oven fire is removed into a steel receptacle for disposal. A steel receptacle is required as there may be hot embers in the ash pile from the previous day.

The oven floor can be swept with a broom to remove the bulk of the ash and occasionally a wipe down with a damp (not wet) rag/cloth over the floor bricks.

In the same fashion that you would start a camp fire or BBQ, set a new fire inside the door of the oven. Using clean dry hardwood, 2 or 3 pieces of split log is sufficient to start the fire. Once the fire is established (15min) push the fire to the desired position in the oven and add a couple more pieces of wood.

At this stage the Plug Door can be inserted into the oven mouth and the oven will quickly re-heat to required temperature for cooking.

Depending on the size of the oven and the cooking load and style, additional timber fuel will need to be added every one or two hours during the day. If there is a period of no cooking during the day, the fire can be left smouldering for hours and topped up prior to the next cooking session. The oven temperature is controlled by the size of the fire. An external thermometer is sometimes used although with only a little experience, an operator quickly gains a feel for the size of the fire required. The oven temperature is very stable and operators find different thermal zones within the oven very useful.

When cooking is finished for the day, the Plug Door should be reinserted and the fire can safely be left for clean out the next morning. (It can be beneficial to place a couple of pieces of fire wood in the oven, away from the fire, overnight to dry out thoroughly for the next morning's fire up. This will aid in easy firing with minimal smoke production.)

Please refer to Wood Burning Characterisitics for more information.

Daily Operation, Wood with Gas Backup Oven

This style of oven requires a similar regime to the Wood Only oven.

The ash from the previous day should be removed each morning and the oven prepared as per the wood oven. In some cases the wood fire may only be replaced every couple of days as the fire size may be small due to the use of the gas fuel.

The gas system can be used to pre-heat the oven each morning and a small wood fire used only in times of cooking. The gas system is very simple to operate. One switch to turn on and the gas system will automatically light and operate all day maintaining the Set Value (SV) temperature set into the temperature controller on the door of the control cabinet. This SV temperature is the actual floor tile temperature of the oven. This is found to be the best register for consistent pizza production. 260°C (500°F)-320°C (608°F) is common for most ovens. The chef or operator will best determine the SV for their application. Once set, the SV will remain the same for daily operation.

At times the wood fire will 'take over' from the gas back up. This is when the wood fire is hotter than the SV is set to. In this case the gas will go to lo-flame and if necessary switch off until the oven temperature falls below the SV level. (In this style of oven, the present temperature is displayed on the Gas Cabinet temperature controller as PV display.) The gas system will again automatically restart and maintain oven temperature. If the oven is not being used the Plug Door can be left in the oven mouth and the gas system will automatically cycle on-off to maintain SV temperature. Energy loss is minimal.

At the end of the day the gas system is switched off, the Plug Door should be again placed in the oven door to retain heat overnight. It is acceptable and safe to leave the gas system running overnight or between shifts as the energy input is minimal while the oven is not being used.

Please refer to Wood Burning Characterisitics for more information.

Daily Operation, Full Gas Oven

Full Gas oven operation is the most simple. It is a matter to switch the control On and Off. The SV temperature is selected by the chef or operator and the oven will automatically maintain the oven to this temperature.

The Full Gas oven uses a similar system to the Gas Backup oven but has additional power to allow the gas system to be the sole energy input and maintain the high performance of the Beech Wood Fired Oven.

Oven cleaning may not be required every morning as the only debris should be food stuffs which mostly disappear into dust each day.

To conserve energy the Plug Door should be inserted when the oven is not in use. Full Gas Beech ovens may feature an optional decorative display flame. This can be a feature in any restaurant and is completely safe to leave burning any time. (Beech Ovens gas systems use high quality components with state-of-the-art flame management and safety systems.)

COOKING IN THE OVEN

The pizzas should be turned and moved about to suit their cooked condition. The chef soon becomes familiar with the ambient and reflected heat conditions in the oven and moves the pizzas around to suit this. If further assistance is required please contact us for a free Cooking Video.

The oven can be used for cooking foods other than pizzas and many chefs experiment with different wood types to get interesting flavours. Food can be roasted in cooking trays. Please see the Cooking section for more information about cooking in a Beech oven.

REGULAR FLUE MAINTENANCE

IT IS CRITICAL THAT THE FLUE BE CLEANED OUT ON A THREE MONTHLY BASIS TO REDUCE THE DANGER OF FLUE FIRE CAUSED BY THE BUILD UP OF SOOT AND FAT IN THE FLUE. CONTACT US IF YOU REQUIRE MORE INFORMATION ON THIS MATTER.

Install an Oven

The Beech Oven is available in any size or shape. Our range of standard round ovens varies from 900mm (35.4") to 1800mm (70.9") internal diameter. The most popular size is the model WO1300, having a capacity of approximately 90 x 25cm (9.8") pizzas per hour. The following architectural details apply in general to all models but measurements refer to the model WO1300 specifically.

The oven is delivered in two sections weighing 1400kg (3086.4lbs) in total. Due to the sheer weight and size of the oven it is necessary to have clear access for handling equipment, installation and a structurally adequate (preferably concrete) floor. The oven can operate on wood alone or with the assistance of gas. If the oven is fitted with the optional gas back up it requires a 19mm (0.75") gas line and mains electricity supply. Standard electrical components are rated for 240 volts AC, 50Hz, although special voltage and frequency ratings can be supplied. The gas main diameter will vary depending on the type of gas to be used. Refer to Gas and Energy Specifications.

The oven arrives as a steel cylinder 200mm (7.9") wider than the model number requested eg. the 1300 model has a 1500mm (59.1") outside diameter, standing on its own steel legs. To the outside skin is placed 50mm (2") of supplied ceramic insulating material and a 25mm (1") air gap should be allowed. It is from this point that the client builds the outer architectural wall.

	The packaged oven top is delivered on two pallets: the oven itself arrives as a steel cylinder standing on its own steel legs. The packaged oven base, steel legs and other included accessories and materials arrive on the second pallet.
	The assembled oven can be moved by trolley. The oven consists of two sections weighing 1400kg (3086.4lbs) in total. Due to the sheer weight and size of the oven it is necessary to have clear access for handling equipment, installation and a structurally adequate (preferably concrete) floor. Refer to the detailed installation instructions accompanying the oven for the actual procedure. The oven can be moved on its side through a standard door. The plywood protective cover should remain on the hearth until the oven is in its final location. Mechanical handling equipment is essential.
	To the outside skin is placed 50mm of supplied ceramic insulating material. Note the position of the flue and spark arrester box. If the architectural finish is to extend from floor to ceiling, provision must be made for an inspection hatch to allow access to the flue for regular cleaning.
	The oven can be surrounded in any form of non-combustible building material including Brick, stainless steel, colourbond (sheetmetal) corrugated iron, Plasterboard or Fibre Cement. The external temperature would normally be 30°C (86°F) - 40°C (104°F). Contact us for advice on your specific choice of materials.
	Installing a plaster facade to the oven using metal studs. The vertical studs are attached to horizontal top and bottom metal "rails", which can be attached to customwood or the like to give the desired shape. In this instance the bottom rail is attached directly to the concrete floor, the top rail is attached to a customwood "former".

Outer Architectural Wall

The oven can be surrounded by any form of non-combustible building material including brick, stainless steel, colourbond (sheetmetal) corrugated iron, plasterboard or fibre cement. The external temperature would normally be 30°C (86°F) - 40°C (104°F).

Refer to Drawings 1 and 4 under Technical Documents for most standard details. Beech Ovens can also design your architectural finishes for you.

Detailed information about building architectural walls is available here by clicking on the type of wall you wish to build:

Type of wall:

Brick Wall (under construction)
Metal Stud Wall (PDF, 201 kB)
Beech Custom Rectangular Façade (under construction)

Duct Work and Gas Train

The architectural wall may be constructed to be full floor to ceiling height to cover ductwork or constructed to the top of the oven only, with exposed ductwork or canopy. If the architectural wall is built to the ceiling it will require an inspection hatch for access to the ductwork for maintenance and cleaning purposes. The construction of the ductwork is the responsibility of the client. Standard duct size is 300mm (11.8") x 300mm (11.8") or equivalent round section. Refer to Venting Requirements for standard duct details.

The optional backup gas control panel is located on one of the two front legs or can be fitted into a cupboard depending on the kitchen layout. This panel is sized approx 200mm (7.9") x 600mm (23.6") and is designed to be built in to the circular wall. The stainless steel box is recessed into the outside diameter of the wall by 50mm (2") to avoid interference with kitchen operation.

The flue exhausts from the top of the oven directly above the oven entrance. The flue can be connected to an existing kitchen exhaust system or preferably will vent naturally through a dedicated flue system. We strongly recommend that local authorities be consulted regarding compliance to local regulation for all flue connections. Beech Ovens offer a variety of exhaust accessories; refer to Venting Requirements for details.

Hearth

Beech Ovens recommends the use of a hearth at the mouth of the oven. Beech Ovens offer a stainless steel hearth, which attaches to the oven body as a standard accessory. Beech Ovens are able to supply design drawings for all construction work.

A rectangular lintel around the mouth of the oven makes construction of the architectural wall simple. Lintels are also available for openings for windows or char grills.

Installation

If the oven is to be installed in a new development it is important to do so at an early stage to ensure ease of access. If the oven is going into an existing building, assuming satisfactory access, it can normally be installed in 4 hours. The oven will fit in standard elevators for multistorey developments. Subsequent work includes the architectural finishing, duct work installation and final commissioning.

Further Information

We hope that we have addressed the most common architectural questions but please contact us if you require further information.