Work Procedure

WET PIPE SPRINKLERS SYSTEM, FIRE PROTECTION

GENERAL

1.1 REFERENCES
1.2 GENERAL REQUIREMENTS
1.3 SUBMITTALS
1.4 DELIVERY AND STORAGE

PART 2 PRODUCTS

2.1 GENERAL EQUIPMENT REQUIREMENTS
2.2 ABOVEGROUND PIPING SYSTEMS
2.3 ALARM CHECK VALVE ASSEMBLY
2.4 WATER MOTOR ALARM ASSEMBLY
2.5 ALARM INITIATING AND SUPERVISORY DEVICES
2.6 FIRE DEPARTMENT CONNECTION
2.7 SPRINKLERS
2.8 ACCESSORIES

PART 3 EXECUTIONS

3.1 INSTALLATION REQUIREMENTS
3.2 ABOVE GROUND PIPING INSTALLATION
3.3 PRELIMINARY TESTS
3.4 FINAL ACCEPTANCE TEST


WET PIPE SPRINKLER SYSTEM, FIRE PROTECTION

PART 1 GENERAL

1.1 REFERENCES
The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

  • ASTM A 47 – (1990) Ferritic Malleable Iron Castings
  • ASTM A 53 – (1995) Pipe, Steel, Black and Hot Dipped, Zinc Coated Welded and Seamless
  • ASTM A 183 – (1983; R 1990) Carbon Steel Tract Bolts and Nuts
  • ASTM A 795 – (1995 93) Black and Hot Dipped Zinc Coated (Galvanized) Welded and Seamless Steel Pipe for Fire Protection Use

AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)

  • ASME B16.1 – (1989) Cast Iron Pipe Flanges and Flanged Fittings
  • ASME B16.3 – (1992) Malleable Iron Threaded Fittings
  • ASME B16.11 – (1991) Forged Fittings, Socket Welding and Threaded
  • ASME B16.21 – (1992) Nonmetallic Flat Gaskets for Pipe Flanges
  • ASME B18.2.1 – (1981; Supple 1991; R 1992) Square and Hex Bolts and Screws (Inch Series)
  • ASME B18.2.2 – (1987; R 1993) Square and Hex Nuts (Inch Series)
  • AWWA C203 – (1991) Coal tar Protective Coatings and Linings for Steel Water Pipelines – Enamel and Tape Hot Applied
  • AWWA C900 – (1989) (900a) Poly Vinyl Chloride (PVC) Pressure Pipe, 4I (110 mm) through 121 (300 mm) for Water Distribution

FACTORY MUTUAL ENGINEERING AND RESEARCH (FM)

  • FM P7825 – (1994; Supple I, II & III) Approval Guide

MANUFACTURERS STANDARDIZATION SOCIETY OF THE VALVE AND FITTINGS INDUSTRY (MSS)

  • MSS SP 71 – (1990) Cast Iron Swing Check Valves, Flanges and Threaded Ends

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

  • NFPA 13 – (1996) Installation of Sprinkler Systems
  • NFPA 13R – (1994) Installation of Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height.
  • NFPA 14 – (1996) Installation of Standpipe and Hose Systems.
  • NFPA 24 – (1995) Installation of Private Fire Service Mains and Their Appurtenances
  • NFPA 231C – (1995) Rack Storage of Materials
  • NFPA 1963 – (1993) Fire Hose Connections

 UNDERWRITERS LABORATORIES (UL)

  • UL 01 – (1994; Supple) Building Materials Directory
  • UL 04 – (1994; Supple) Fire Protection Equipment Directory
  • UL 668 – (1989) Hose Valves For Fire Protection Service

SAUDI ARABIAN STANDARDS ORGANIZATION

  • SASO 1011 – Black and hot-dipped galvanized steel pipes suitable for screwing.
  • SASO 1013 – Welded plain-end steel tubes and pipes for general use.
  • SASO 1014 – Socket and spigot ductile cast iron pipes for pressure pipelines.

1.2 GENERAL REQUIREMENTS

Wet pipe sprinkler system shall be provided in all areas of the buildings as shown on drawings. The sprinkler system shall provide fire sprinkler protection for the entire area. Except as modified herein, the system shall be hydraulically designed and installed in accordance with NFPA 13, NFPA 14, and the listed criteria. Pipe shall be determined by hydraulic calculation.

Hydraulic Design

The system shall be hydraulically designed to discharge a minimum density as required to suite the project in accordance with NFPA 13. Hydraulic calculations shall be in accordance with the Area/Density Method of NFPA 13. All water flow availability and flow test shall be determined.

Hose Demand

An allowance for exterior and interior hose streams shall be added to the sprinkler system demand as required to meet NFPA 13, NFPA 14 and the listed criteria.
1.3 SUBMITTALS

Sprinkler System Equipment.

Manufacturer’s Catalog Data for each separate piece of equipment proposed for use in the system. Data shall indicate the name of the manufacturer of each item of equipment, with data highlighted to indicate model, size, options, etc. proposed for installation. In addition, a complete equipment list which includes equipment description, model number and quantity shall be provided.

SHOP DRAWINGS

Sprinkler System Shop Drawings;

Detail drawings showing the complete design of the fire sprinkler system conforming to the requirements established for working plans as prescribed in NFPA 13. Drawings shall include plan and elevation views which establish that the equipment will fit the allotted spaces with clearance for installation and maintenance. Each set of drawings shall include the following:

  •  Descriptive index of drawings in the submittal with drawings listed in sequence by drawing number. A legend identifying device symbols, nomenclature, and conventions used.
  •  Floor plans drawn to a scale not less than 1:100 which clearly show locations of sprinklers, risers, pipe hangers, seismic separation assemblies, sway bracing, inspector’s test connections, drains, and other applicable details necessary to clearly describe the proposed arrangement. Each type of fitting used and the locations of bushings, reducing couplings, and welded joints shall be indicated.
  •  Actual center to center dimensions between sprinklers on branch lines and between branch lines; from end sprinklers to adjacent walls; from walls to branch lines; from sprinkler feed mains, cross mains and branch lines to finished floor and roof or ceiling. A detail shall show the dimension from the sprinkler and sprinkler deflector to the ceiling in finished areas.
  •  Longitudinal and transverse building sections showing typical branch line and cross main pipe routing as well as elevation of each typical sprinkler above finished floor.
  •  Details of each type of riser assembly; pipe hanger; sway bracing for earthquake protection,
  • and restraint of underground water main at point of entry into the building, and electrical devices and interconnecting wiring.

As Built Drawings;

As built drawings, no later than 14 working days after completion of the Final Tests. The sprinkler system shop drawings shall be updated to reflect as built conditions after work is completed and shall be on full size hard copy and reproducible soft copy in Compact Discs.

TEST PROCEDURES

Proposed test procedures for piping hydrostatic test, testing of alarms, at least 14 days prior to the start of related testing.

Preliminary Tests

A schedule of preliminary tests, at least 14 days prior to the proposed start of the tests.

Final Test

Upon successful completion of tests specified under PRELIMINARY TESTS, written notification shall be given to the Contracting Officer of the date finished areas.

  •  Longitudinal and transverse building sections showing typical branch line and cross main pipe routing as well as elevation of each typical sprinkler above finished floor.
  •  Details of each type of riser assembly; pipe hanger; sway bracing for earthquake protection, and restraint of underground water main at point of entry into the building, and electrical devices and interconnecting wiring.

Schedules

A work schedule for the entire scope of works shall be submitted to the client on the start up of the project. The proposed preliminary and final test dates shall be informed to the client 2 (two) weeks in advance.
Certificates

Contractor’s Material & Test Certificates

Certificates, as specified in NFPA 13, shall be completed and signed by the Contractor’s Representative performing required tests for both underground and aboveground piping.

Operation and Maintenance Manuals

Sprinkler System;

Manuals shall be in loose leaf binder format and grouped by technical sections consisting of manufacturer’s standard brochures, schematics, printed instructions, general operating procedures, and safety precautions. The manuals shall list routine maintenance procedures possible breakdowns, and repairs, and troubleshooting guide. This shall include procedures and instructions pertaining to frequency of preventive maintenance, inspection, adjustment, lubrication and cleaning necessary to minimize corrective maintenance and repair.

1.4 DELIVERY AND STORAGE

Equipments placed in storage shall be stored with protection from the weather, humidity and temperature variations, dirt and dust or other contaminants.

PART 2 PRODUCTS

2.1 GENERAL EQUIPMENT REQUIREMENTS

Requirements for Fire Protection Service

Nameplates

Major components of equipment shall have the manufacturer’s name, address, type or style, model or serial number, and catalog number on a plate permanently affixed to the item of equipment.

2.2 ABOVEGROUND PIPING SYSTEMS

Aboveground piping shall be steel.

Steel Piping System

Steel Pipe

Except as modified herein, steel pipe shall be seamless black steel as permitted by NFPA 13 and shall conform to applicable provisions of ASTM A 795 or ASTM A 53. Pipe shall be Schedule 40/ Schedule 80 as per specific project specs. Pipe shall be marked with the name of the manufacturer, kind of pipe, and ASTM designation.

Fittings for Non Grooved Steel Pipe

Fittings shall be steel conforming to ASME B16.9 or ASME B16.11, or malleable iron conforming to ASME B16.3. Steel press fittings shall be approved for fire protection systems. Fittings into which sprinklers, drop nipples or riser nipples (sprigs) are screwed shall be threaded type. Plain end fittings with mechanical couplings, fittings which use steel gripping devices to bite into the pipe and segmented welded fittings shall not be used.

Flanges

Flanges shall conform to NFPA 13 and ASME B16.1. Gaskets shall be non asbestos compressed material in accordance with ASME B16.21, 1.6 mm thick, and full face or self centering flat ring type. Bolts shall be squarehead conforming to ASME B18.2.1 and nuts shall be hexagon type conforming to ASME B18.2.2.

Pipe Hangers

Hangers and spacing shall be listed in UL 04 or FM P7825 and of the type suitable for the application, construction, and pipe type and sized involved.

Valves

Control Valve and Gate Valve

Manually operated sprinkler control valve and gate valve shall be outside stem and yoke (OS&Y) type and shall be listed in UL 01 or FM P7825.

Check Valve

Check valve 50 mm and larger shall be listed in UL 01 or FM P7825. Check valves 100 mm and larger shall be of the swing type with flanged cast iron body and flanged inspection plates, shall have a clear waterway and shall meet the requirements of MSS SP 71, for Type 3 or 4.

Fire Hose Cabinets

Hose Rack Cabinet:

Type FHC-1 surface mounted type, with steel body, trim and door, finished with gauge and door 20
gauge thickness. Door to have full panel double strength glass with ‘FIRE HOSE’ decal.

Hose rack cabinet to be supplied from factory with the following equipment:

  •  One 65 mm pressure restricting angle valve,
  •  One 65 mm x 40 mm brass reducer,
  •  One steel hose rack with rack nipple,
  •  One 40 mm unlined linen fire hose 30 m long
  •  With brass hose couplings attached
  •  One 40 mm brass nozzle, 250 mm long, 15 mm discharge, with satin brass finish,
  • Alarm Check Valve Assembly

Assembly shall include an alarm check valve, standard trim piping, pressure gauges, bypass, retarding chamber, testing valves, main drain, and other components as required for a fully operational system.

2.3 WATER MOTOR ALARM ASSEMBLY

Assembly shall include a body housing, impeller or pelton wheel, drive shaft, striker assembly, gong, wall plate and related components necessary for complete operation. Minimum 20 mm galvanized piping shall be provided between the housing and the alarm check valve. Drain piping from the body housing shall be minimum 25 mm galvanized and shall be arranged to drain to the outside of the building. Piping shall be galvanized both on the inside and outside surfaces.

2.4 ALARM INITIATING AND SUPERVISORY DEVICES

Sprinkler Water flow Indicator Switch, Vane Type

Switch shall be vane type with a pipe saddle and cast aluminum housing. The electro mechanical device shall include a flexible, low density polyethylene paddle conforming to the inside diameter of the fire protection pipe. The device shall sense water movements and be capable of detecting a sustained flow of 38 L/min or greater. The device shall contain a retard device adjustable from 0 to 90 seconds to reduce the possibility of false alarms caused by transient flow surges. The switch shall include two SPDT (Form C) contacts, and shall be equipped with a silicone rubber gasket to assure positive water seal and a dustproof cover and gasket to seal the mechanism from dirt and moisture.

Sprinkler Pressure (Water flow) Alarm Switch

Pressure switch shall include a metal housing with a neoprene diaphragm, SPDT snap action switches and a 15 mm NPT male pipe thread. The switch shall have a maximum service pressure rating of 1207 kPa. There shall be two SPDT (Form C) contacts factory adjusted to operate at 28 to 55 kPa. The switch shall be capable of being mounted in any position in the alarm line trim piping of the alarm check valve.

Valve Supervisory (Tamper) Switch

Switch shall be suitable for mounting to the type of control valve to be supervised open. The switch shall be tamper resistant and contain one set of SPDT (Form C) contacts arranged to transfer upon removal of the housing cover or closure of the valve of more than two rotations of the valve stem.

Sprinkler Zones

The sprinkler system shall be zoned using floor control valves for each sprinklered area. The system shall be zoned in accordance with the smoke compartment configuration.

2.5 FIRE DEPARTMENT CONNECTION

Fire department connection shall be projecting type with cast brass body, matching wall escutcheon lettered “Auto Sprinkler” with a chromium plated finish. The connection shall have two inlets with individual self closing clappers, caps with drip drains and chains. Female inlets shall have 65 mm diameter American National Fire Hose Connection Screw Threads (NH) per NFPA 1963.

2.6 SPRINKLERS

General: Automatic sprinkler heads shall be UL and ULC Listed and FM approved fusible element type. Sprinkler heads shall be with nominal 1/2 inch (12.7 mm) discharge orifice, 5.6 K-Factor, maximum working pressure of 175 psi, and temperature rating of 93C for kitchen and 68C for other areas. Sprinkler heads shall be located where shown on the drawings, and shall be installed in accordance with NFPA 13 Standards. Sprinklers shall be used in accordance with their listed spacing limitations. Temperature classification shall be as required. Sprinklers in high heat areas including attic spaces or in close proximity to unit heaters shall have temperature classification in accordance with NFPA 13.

Upright Sprinkler

Upright Sprinkler Heads: Shall be bright chrome plated. Fusible alloy element is sealed into bronze center strut by a stainless steel ball. When the alloy melts at its rated temperature, the ball is forced upward into center strut, releasing the two ejectors and operating the sprinkler.

Pendent Sprinkler

Pendant Sprinkler Heads (Recessed): Shall be recessed pendent type (adjustable), bright chrome, 60.32 mm (2-3/8 inch) length and 38 mm (1-1/2 inch) width (across frame arms). Each sprinkler head shall be provided with adjustable chrome plated recessed metal escutcheon, 3-1/4 inch dia; all nominal sizes. Fusible alloy element is sealed into bronze center strut by a stainless steel ball. When the alloy melts at its rated temperature, the ball is forced upward into center strut, releasing the two ejectors and operating the sprinkler. Provide recessed type sprinkler heads at all other ceilings, except gypsum board.

Sidewall Sprinkler Type

Sidewall sprinkler shall have a nominal 12.7 mm orifice. Sidewall sprinkler shall have a polished chrome finish. Sidewall sprinkler shall be the quick response extended coverage.

Upright sprinkler type SP-5

Shall be brass construction and shall have a nominal 12.7 mm or 13.5 mm orifice and intermediate temperature rating suitable for ordinary hazard application such as elevator machine rooms.

2.7 ACCESSORIES

Sprinkler Cabinet

Spare sprinklers shall be provided in accordance with NFPA 13 and shall be packed in a suitable metal or plastic cabinet. Spare sprinklers shall be representative of, and in proportion to, the number of each type and temperature rating of the sprinklers installed. At least one wrench of each type required shall be provided.

Pendent Sprinkler Escutcheon

Escutcheon shall be one piece metallic type with a depth of less than 20 mm and suitable for installation on pendent sprinklers. The escutcheon shall have a factory finish that matches the pendent sprinkler heads.

Pipe Escutcheon

Escutcheon shall be polished chromium plated zinc alloy, or polished chromium plated copper alloy. Escutcheons shall be either one piece or split pattern, held in place by internal spring tension or set screw.

Sprinkler Guard

Guard shall be a steel wire cage designed to encase the sprinkler and protect it from mechanical damage. Guards shall be provided on sprinklers where required.

Identification Sign

Valve identification sign shall be minimum 150 mm wide x 50 mm high with enamel baked finish on minimum 1.214 mm steel or 0.6 mm aluminum with red letters on a white background or white letters on red background. Wording of sign shall include, but not be limited to “main drain,” “auxiliary drain,” “inspector’s test,” “alarm test,” “alarm line,” and similar wording as required identifying operational components.

PART 3 EXECUTIONS

3.1 INSTALLATION REQUIREMENTS

The installation shall be in accordance with the applicable provisions of NFPA 13 and publications referenced therein. Installation of in rack sprinklers shall comply with applicable provisions of NFPA 231C.

3.2 ABOVE GROUND PIPING INSTALLATION

Piping shall be run straight and bear evenly on hangers and supports.

Piping in Exposed Areas

Exposed piping shall be installed so as not to diminish exit access widths, corridors or equipment access. Exposed horizontal piping, including drain piping, shall be installed to provide maximum headroom.

Piping in Finished Areas

In areas with suspended or dropped ceilings and in areas with concealed spaces above the ceiling, piping shall be concealed above ceilings. Piping shall be inspected, tested and approved before being concealed. Risers and similar vertical runs of piping in finished areas shall be concealed.

Pendent Sprinklers

All type construction, the protection area per sprinkler shall be 130 sq ft (12.1 m2) and pipe sizes and arrangement shall be accordance with NFPA Stds. Branch line pipe not exceed 8 sprinkler on either side of across main. Occupancy is classified as ordinary hazard and where more than 8 sprinklers on branch line are necessary, the line may be increased to 9 sprinklers by making the two end lengths 1 inch and 1-1/4 inch respectively. And sizes thereafter standard .Ten sprinklers may be placed on a branch line making the two end length 1 inch and 1-1/4 respectively and feeding the length sprinkler by a 2-1/2 inch pipe.

Pipe scheduled shall be proceed the following sizes,

• 1 inch – 2 numbers of sprinkler ,
• 1-1/4 inch –3 numbers of sprinkler,
• 1-1/2 inch – 5 numbers of sprinkler,
• 2 inch –10 numbers of sprinkler,
• 2-1/2 inch – 20 numbers of sprinkler,
• 3 inch – 40 numbers of sprinkler,
• 4 inch – unlimited numbers of sprinkler.

The maximum distance between sprinkler on the branch line exceeds 12ft (3.7 meter) or distance between two branch lines exceed 12ft (3.7 meter)
The number of sprinklers for a given pipe size shall be in accordance with Std.

Fabrication and welding for main line installation

Fabrication and welding methods which comply with all of the requirement of AWS D 10.9 Standard for building service piping, Level R-3 are acceptable means of joining fire protection piping .welding sections of sprinkler piping in place inside the building shall not be permitted. Section of branch lines, cross main or risers above 2 inch pipe shall be welded

Drop nipples to pendent sprinklers shall consist of minimum 25 mm pipe with a reducing coupling into which the sprinkler shall be threaded. Hangers shall be provided on arm overs to drop nipples supplying pendent sprinklers when the arm over exceeds 300 mm. Where sprinklers are installed below suspended or dropped ceilings, drop nipples shall be cut such that sprinkler ceiling plates or escutcheons are of a uniform depth throughout the finished space. The outlet of the reducing coupling shall not extend more than 25 mm below the underside of the ceiling. On pendent sprinklers installed below suspended or dropped ceilings, the distance from the sprinkler deflector to the underside of the ceiling shall not exceed 100 mm.

Pendent Sprinkler Locations

Pendent sprinklers in suspended ceilings shall be a minimum of 150 mm from ceiling grid.

Upright Sprinklers

Riser nipples or “springs” to upright sprinklers shall contain no fittings between the branch line tee and the reducing coupling at the sprinkler. Riser nipples exceeding 750 mm in length shall be individually supported.

Pipe Joints

Pipe joints shall conform to NFPA 13, except as modified herein. Not more than four threads shall show after joint is made up. Welded joints will be permitted, only if welding operations are performed as required by NFPA 13 at the Contractor’s fabrication shop, not at the project construction site. Flanged joints shall be provided where indicated or required by NFPA 13. Grooved pipe and fittings shall be prepared in accordance with the manufacturer’s latest published specification according to pipe material, wall thickness and size. Grooved couplings and fittings shall be from the same manufacturer.

Reducers

Reductions in pipe sizes shall be made with one piece tapered reducing fittings. The use of grooved end or rubber gasketed reducing couplings will not be permitted. When standard fittings of the required size are not manufactured, single bushings of the face type will be permitted. Where used, face bushings shall be installed with the outer face flush with the face of the fitting opening being reduced. Bushings shall not be used in elbow fittings, in more than one outlet of a tee, in more than two outlets of a cross, or where the reduction in size is less than 15 mm.

Pipe Penetrations

Cutting structural members for passage of pipes or for pipe hanger fastenings will not be permitted. Pipes that must penetrate concrete or masonry walls or concrete floors shall be core drilled and provided with pipe sleeves. Each sleeve shall be Schedule 40 galvanized steel, ductile iron or cast iron pipe and shall extend through its respective wall or floor and be cut flush with each wall surface. Sleeves shall provide required clearance between the pipe and the sleeve per NFPA 13. The space between the sleeve and the pipe shall be firmly packed with mineral wool insulation. Where pipes pass through fire walls, fire partitions, or floors, a fire seal shall be placed between the pipe and sleeve. In penetrations which are not fire rated or not a floor penetration, the space between the sleeve and the pipe shall be sealed at both ends with plastic waterproof cement which will dry to a firm but pliable mass or with a mechanically adjustable segmented elastomer seal.

Escutcheons

Escutcheons shall be provided for pipe penetration of ceilings and walls. Escutcheons shall be securely fastened to the pipe at surfaces through which piping passes.

Inspector’s Test Connection

Unless otherwise indicated, test connection shall consist of 25 mm pipe connected to the remote branch line; a test valve located approximately 2 meters above the floor; a smooth bore brass outlet equivalent to the smallest orifice sprinkler used in the system; and a painted metal identification sign affixed to the valve with the words “Inspector’s Test.” The discharge orifice shall be located outside the building wall directed so as not to cause damage to adjacent construction or landscaping during full flow discharge.

Drains

Main drain piping shall be provided to discharge at a safe point outside the building. Auxiliary drains shall be provided as required by NFPA 13 except that drain valves shall be used where drain plugs are otherwise permitted. Where branch lines terminate at low points and form trapped sections, such branch lines shall be manifolded to a common drain line.

Installation of Fire Department Connection

Connection shall be mounted on the exterior wall approximately 900 mm above finished grade. The piping between the connection and the check valve shall be provided with an automatic drip in accordance with NFPA 13 and arranged to drain to the outside.

Identification Signs

Signs shall be affixed to each control valve, inspector test valve, main drain, auxiliary drain, test valve, and similar valves as appropriate or as required by NFPA 13. Hydraulic design data nameplates shall be permanently affixed to each sprinkler riser as specified in NFPA 13.

3.3 PRELIMINARY TESTS

Hydrostatic Testing

Aboveground piping shall be hydrostatically tested in accordance with NFPA 13 at not less than 350 kPa in excess of maximum system operating pressure and shall maintain that pressure without loss for 2 hours. There shall be no drop in gauge pressure or visible leakage when the system is subjected to the hydrostatic test. The test pressure shall be read from a gauge located at the low elevation point of the system or portion being tested.

Testing of Alarm Devices

Each alarm switch shall be tested by flowing water through the inspector’s test connection. Each water operated alarm devices shall be tested to verify proper operation.

Main Drain Flow Test

Following flushing of the underground piping, a main drain test shall be made to verify the adequacy of the water supply. Static and residual pressures shall be recorded on the certificate specified in paragraph SUBMITTALS. In addition, a main drain test shall be conducted each time after a main control valve is shut and opened.

3.4 FINAL ACCEPTANCE TEST

A technician employed by the installing Contractor shall be present for the final tests and shall provide a complete demonstration of the operation of the system. This shall include operation of control valves and flowing of inspector’s test connections to verify operation of associated waterflow alarm switches. After operation of control valves has been completed, the main drain test shall be repeated to assure that control valves are in the open position. In addition, the representative shall have available copies of as built drawings and certificates of tests previously conducted.