A Quick Guide To The Duct System’s Components

Duct systems are air delivery and removal passageways or conduits used in heating, ventilation, and air conditioning (HVAC). Duct systems deliver ventilation air in addition to supply air. As a result, air ducts help to keep the air in your home clean and comfortable.

Ductwork is another term for a duct system. Duct design is the process of planning (layout), sizing, optimizing, detailing, and figuring out how much pressure is lost in a duct system, as well as how much it costs.

Components of the duct system

Apart from the ducts themselves, complete ducting systems incorporate a variety of additional components.

Vibration isolators

A duct system is frequently initiated at an air handler. The blowers in the air handler can generate significant vibration, and the duct system’s large surface area would transmit this noise and vibration to the building’s occupants. To avoid this, vibration isolators (flexible sections) are typically installed in the duct immediately preceding and following the air handler. These sections are made of a rubberized canvas-like material that allows the air handler to vibrate freely without transferring much vibration to the attached ducts. The same flexible section can help cut down on noise when the blower is turned on and positive air pressure is brought into the ductwork.


The supply air trunk duct will frequently fork downstream of the air handler, supplying air to numerous individual air outlets such as diffusers, grilles, and registers. When a system is designed with the main duct branching off into numerous subsidiary branch ducts, take-off fittings allow a small portion of the flow in the main duct to be diverted into each branch duct.

Take-offs may be installed in circular or rectangular openings cut into the main duct’s wall. Typically, the take-off has numerous small metal tabs that are bent to connect it to the main duct. Round fittings are referred to as “spin-in fittings.” Other take-off designs use a snap-in attachment method, which is sometimes combined with an adhesive foam gasket for better sealing.

Stack boots and heads

Ducts, particularly in homes, are frequently required to allow air to travel vertically through relatively thin walls. These vertical ducts are referred to as stacks and are made up of extremely wide and relatively thin rectangular or oval sections. A stack boot connects an ordinary large round or rectangular duct to the thin wall-mounted duct at the bottom of the stack. At the top, a stack head can be used to reconnect to standard ductwork, while a registered head can be used to connect to a wall-mounted air register.

Frequently, ducting systems must include a mechanism for adjusting the volume of airflow to various components of the system. This function is provided by volume control dampers (VCDs; not to be confused with smoke or fire dampers).

Apart from the regulation provided at the registers or diffusers that distribute air between rooms, dampers can be installed within the ducts themselves. These dampers may be manually operated or automatically operated. In simple systems, zone dampers provide automatic control; in more complex systems, variable air volume (VAV) provides control.

Smoke and fire dampers

Smoke and fire dampers are typically found in ductwork that passes through a firewall or fire curtain. A motor, referred to as an actuator, is used to drive smoke dampers. A probe connected to the motor is installed in the run of the duct to detect smoke, either in the air being extracted from or supplied to a room or in any other location along the run of the duct. Once smoke is detected, the actuator closes the smoke damper automatically until it is manually reopened.

Fire dampers are located in the same locations as smoke dampers, depending on the intended use of the area immediately following the firewall. They are not activated by any electrical system, in contrast to smoke dampers (which is an advantage in the case of an electrical failure where the smoke dampers would fail to close).

Gravity-operated fire dampers are vertically mounted, whereas spring-operated fire dampers are horizontally mounted. The most critical feature of a fire damper is a mechanical fusible link, which is a piece of metal that melts or breaks at a predetermined temperature. This enables the damper to close (either by gravity or spring force), effectively sealing the duct, containing the fire and blocking the air required for combustion.

Turning vanes

Turning vanes are installed within ductwork at direction changes (e.g., 90° turns) to reduce turbulence and resistance to airflow. The vanes guide the air, allowing it to more easily follow the direction change.


Plenums are the HVAC system’s central distribution and collection units. The return plenum transports air from a collection of large return grilles (vents) or bell mouths to a central air handler. The supply plenum directs air from the central unit to the rooms that the system is designed to heat or cool. They must be meticulously planned into the ventilation design process.

Terminals units

While single-zone constant air volume systems typically do not include these, multi-zone systems frequently do. Typically, each thermal zone has a single terminal unit. Terminal units come in a variety of configurations, including VAV boxes (single or dual duct), fan-powered mixing boxes (in parallel or series configurations), and induction terminal units. Additionally, terminal units may incorporate a heating or cooling coil.

Air terminals

Air terminals are the outlets for supplying air and the inlets for return or exhausting air. Diffusers are most frequently used for supply, but grilles and, for very small HVAC systems (such as those found in residences), registers are also frequently used. Although return or exhaust grilles are primarily used for aesthetic purposes, some incorporate an air filter and are referred to as “filter returns.” For more details, you may contact duct manufacturers in India. They will be more than happy to answer your questions.


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The Advantages of HDPE Pipes

HDPE pipe is a flexible plastic pipe that is frequently used to replace aging concrete or steel main pipelines. Made of thermoplastic HDPE (high-density polythene), this material’s high level of impermeability and strong molecular bond make it ideal for high-pressure pipelines. HDPE pipe is used worldwide for water mains, gas mains, sewer mains, slurry transfer lines, rural irrigation, fire system supply lines, electrical and communication conduits, and stormwater and drainage pipes.

Benefits of HDPE Pipes

Polyethylene’s toughness and chemical resistance, as well as its corrosion resistance and lightweight, have contributed to its increasing use in situations requiring cost-effective and durable fluid and gas piping systems. According to a press release from the Plastics Pipe Institute, “PE piping has been used in Europe and America for water and other fluids since the 1950s due to its durability, leak-free joints, corrosion resistance, and long-term cost-effectiveness.”

Butt welding, electrofusion welding, socket welding, or extrusion welding can all be used to join HDPE pipes. These joints heat the pipe during the joining process, resulting in an entirely homogeneous joint that is as strong as, if not stronger than, the existing pipe on either side of the weld. There is no need for rubber seals or jointing chemicals, which are used to join PVC pipes and contribute to environmental toxicity and increase the likelihood of failure over time. According to the suppliers of HDPE pipe, PE is less prone to root intrusion and maintains the pipeline’s integrity even when installed in unstable soils.

Since the fusion welding system eliminates the need for anchors or thrust restraint blocks, the joints become fully end-load resistant, lowering material and installation costs. This also enables future excavations closer to the pipeline to be safer, which is critical for high-pressure gas pipelines. Trenchless installation with coils of PE pipe is safer and less intrusive on the surrounding environment.

HDPE pipe systems can be used in a variety of applications, including standard trenching for water mains, fire ring mains, sewer mains, and gas mains pipelines, as well as horizontal drilling for electrical and telecommunications conduits. According to a manufacturer of HDPE systems, HDPE systems are cost-effective to install, have low long-term maintenance costs, and enable the use of less expensive installation techniques such as HDD (horizontal directional drilling), slip-lining, pipe bursting, floating, and submerged pipe.

HDPE pipe is extremely durable and flexible and can be bent on-site to a radius of twenty-five times the nominal pipe diameter (for SDR11 and SDR17 pipe) at or below the ambient temperature of twenty degrees Celsius. This results in significant cost savings when compared to other pipe systems, which require glued fittings, restraints, or thrust blocks for even minor direction changes. Due to HDPE pipe’s high impact resistance and flexibility, it is well suited for installation in dynamic soils, including those prone to earthquakes. Due to its smooth bore and end-to-end jointing methods, HDPE pipe has an extremely high flow capacity. HDPE pipe does not corrode in the environment and retains its flow characteristics over time, in contrast to ferrous piping systems, which rust and develop internal resistance to fluid flow.

Because HDPE pipes are constructed from virgin food-grade polythene, they are safe for the transfer of drinking water, provided that any initial debris has been flushed out. HDPE pipe is resistant to a wide variety of chemicals, allowing it to be used in process plants and in areas with corrosive or acidic environments without the need for protective coatings or galvanizing, as steel pipes require. Due to HDPE’s low thermal conductivity, it can maintain more consistent temperatures when transporting fluids than metal pipes, significantly reducing the need for insulation to control condensation around the pipeline.

Expected lifespan of HDPE Pipes

Although HDPE pipe is frequently estimated to last 50 years, it is more likely to last 100 years. PIPA (Plastics Industry Pipe Association) and the Plastic Pipe Institute (PPI) have both published technical white papers on the design life of HDPE pipes. The PIPA paper is titled “Life Expectancy for Plastics Pipes,” and it states that due to the fifty-year stress regression data, some people incorrectly believe that plastic pipe systems have a fifty-year life expectancy. Indeed, these pipe systems are capable of lasting up to or exceeding 100 years.

PE pipes and fittings were introduced in the mid-1900s for irrigation and water supply applications, but also for gas, fuel, and other industrial applications. The use of this 50-year time interval creates the misconception that it represents a pipe life of 50 years. The actual life of properly manufactured and installed pipe systems cannot be predicted, but can be expected to exceed 100 years before major rehabilitation is required.

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A Guide to DWC HDPE Pipe

DWC Pipes are Double Walled Corrugated Duct Pipes and are manufactured from HDPE Materials. They were specifically created to offer the most cost-effective solutions to those who are looking for replacements of GI, RCC, or PVC Pipes to lay Fibre Electric Cable networks.

DWC HDPE Pipe has been widely used in wastewater collection and transport networks since the 1980s. These DWC HDPE pipelines are very useful for municipal bodies, urban conglomerates, or agricultural drainage.

Buy DWC Pipes in India

DWC HDPE pipe are made of materials that are cost-effective and provide service to the contractor. HDPE Double Wall Corrugated Pipes made of high-density Polyethene have the longest life expectancy.

High-density polyethylene pipes (HDPE) are made from PE 100 and 100 RC materials. Some pipes are resistant, to wear, tear and UV radiation. The pipes can be non-toxic, flexible, and homogeneous with welded or fluted connections. They are resistant to light absorption, can withstand harsh conditions, and are highly productive. Some pipes can be used in power plants and other applications such as rehabilitation, large sewage system, or seawater desalination. Serves the needs of the oil, natural gas, coal combustion residual (CCR), and civil, environmental as well as mining, water, and wastewater industries.

HDPE tube, a type of flexible plastic pipe, is used for fluid transfer. High-pressure pipelines can be made of thermoplastic HDPE, high-density polyethylene. Its high impermeability (and strong molecular link) makes it ideal. HDPE tube is used in various applications around the world, including water, gas, and sewer lines. It is also used for rural irrigation, fire systems, electrical and communications wiring, and stormwater and drainage pipes.

Polyethylene is a tough and chemical-resistant material that has been used in a variety of applications. It is also corrosion-resistant and lightweight, which have all contributed to its increasing popularity as a cost-effective and durable gas and fluid piping system. Plastics Pipe Institute’s press release states that PE pipe has been used to transport water in Europe since the 1950s.

HDPE pipe can be joined with butt welding (electrofusion welding), socket welding (or extrusion welding). In these joints, pipes are heated during joining, resulting in a stronger joint than the pipe on the opposite side. PVC pipe joints do not require rubber seals or jointing chemicals. These methods can increase the possibility of failure and create health concerns. When installed in unstable soils, PE pipelines are less likely to fall victim to root intrusion problems.

Because the joints are fully load-resistant, there is no need for anchors. This makes it easier to dig near the pipeline for future high-pressure gas pipelines. PE Pipe coils make trenchless installation less dangerous and more friendly to the environment.

HDPE Pipe Systems are suitable for many applications. They can be used to standardize trenching for water mains. Horizontal drilling for electrical or telecommunications conduits is also available. According to HDPE manufacturers, HDPE systems cost-effectively install and offer long-term maintenance cost savings.

HDPE pipe has a very high life span and is extremely flexible. HDPE pipes can also be bent in place to a radius of 25x the nominal pipe diameter. This makes it much more economical than other pipe options. Some pipes require thrust blocks and restraints. Other pipes need glued fittings. HDPE pipes are excellent for installation in areas with high earthquake risk and dynamic soils because of their flexibility and resistance to impact. HDPE pipe can flow very well due to its smooth bore design and end-to-end jointing. HDPE pipes are resistant to corrosion in the environment and will keep their flow capability over time.

HDPE pipes can be used to transfer drinking waters as long as any debris is removed. HDPE pipe is highly resistant to chemicals. This allows it to be used in process plants, or around acidic or corrosive environments. HDPE is very resistant to heat and can carry fluids at much lower temperatures than metal pipes. This allows for a reduction in insulation needed to keep condensation from forming around the pipeline.

The life expectancy of HDPE Pipe

HDPE pipes can be expected to last for at least 50 years. However, they are much more likely to last 100 years. PIPA (Plastics Industry Pipe Association), together with the Plastic Pipe Institute PPI, have produced white papers on HDPE design lives. It mentions that people wrongly assume that plastic pipe systems will live for only fifty years because of the 50-year stress reduction data. These pipe systems can be expected to last 100 years. In Australia, PE pipes were developed in the mid-1900s. PE fittings can be used for irrigation or water supply as well as for fuel, gas, and other industrial applications. These 50 years are used to mislead people into believing that it means a 50+ year pipe life. Although the life expectancy for pipe systems that have been properly manufactured and installed cannot be predicted, it can be estimated to be over 100-years before major rehabilitation is needed. PIPA (Plastics Industry Pipe Association), together with the Plastic Pipe Institute has created technical white papers that discuss HDPE pipe design life. “Life Expectancy For Plastics Pipes” was the PIPA paper. It mentions that 50-year stress regression data leads people to believe that plastic pipe systems will live for only fifty years. These pipe systems are reasonably expected to last at least 100 more years.

PE pipes and fittings in Australia were invented during the mid-1900s. The PE pipes were used for irrigation or water supplies, but also fuel, gas, and other industrial applications. These 50 years are used to mislead people into believing that it means a 50+ year pipe lifespan. If pipe systems have been correctly manufactured, installed, and maintained, their actual life can not be predicted but can be expected over 100 years until major rehabilitation.

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DCA and CS – Indian Oil

VEEKAY PLAST is Del Credere Associates cum Consignment Stockists for Indian Oil Corporation Limited for marketing of polymer in Rajasthan state.

Expanding Horizons in Petrochemical Business

The petrochemical sector is a major driver of industrial growth. The per capita consumption of plastics in India is far below the world average. However in the last decade, the Indian polyolefin industry has seen double digit growth offering large potential for further growth.

We are DCA and CS of IndianOil which is focusing on strengthening its petrochemicals business by venturing into downstream polymer units. A world-class Naphtha Cracker and Polymer units are operational at IndianOil’s Panipat Refinery. The technology and capacities of the Naphtha Cracker and Polymer units are world-class, with products ranging from commodity to niche grades. Commissioned on llth March 2010, the Naphtha Cracker complex includes:-

Naphtha Cracker Unit (NCU):

  • World class Naphtha Cracker unit with technology from ABB Lummus located at Panipat, Haryana
  • Design capacity
    • 857 KTA of ethylene
    • 650 KTA of propylene

Downstream Polymer Units

Polypropylene (PP) Unit:

  • Two production lines of 300 KTA each with Spheripol technology license from Basell, Italy.
  • Product portfolio includes entire range of Homopolymers, Block copolymers and Random copolymers

Dedicated HDPE Unit:

  • Dedicated HDPE plant of 300 KTA using Basell (Hostalen) slurry process.
  • Product portfolio includes Unimodal as well as Bimodal HDPE grades for various application segments such as Film, Blow Moulding & Pressure pipes

LLDPE/ HDPE Swing Unit:

    • LLDPE/ HDPE swing plant of 350 KTA capacity based on Sclairtech Solution polymerisation technology of Nova Chemicals, Canada.
    • Product portfolio includes general-purpose LLDPE &HDPE grades, as well as speciality LLDPE grades using 1- Octene as co-monomer for niche application segments.

Our PROPEL brand of petrochemicals is a leader in providing everyday solutions to customers in India.

For Downloading Grade Sheet please click the link below:

Grade Sheet – Propel

For Downloading Petrochemical Brochure please click the link below:

Petrochemical Brochure

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ISO Certifications and Accreditions

VEEKAY PLAST Quality Management System is certified to ISO 9001:2015 by an Accredited Certification Body for both Jaipur and Hyderabad Plant.

VEEKAY PLAST  is certified for

  • ISO 9001:2015
  • ISO 14001:2015
  • ISO 18001:2007
  • ISO 4427-2:2007
  • ISO 4437:2007

Our most recent certificate for registrations can be accessed at the link below.

ISO Certificates

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ISI and TSEC Approved

VEEKAY PLAST  is holder of Technical Specification Evaluation Certificate (TSEC) for its 40/33mm and 50/42mm PLB HDPE DUCT that supports the deployment of the next generation of multiple play FTTx services.

VEEKAY PLAST is the having valid TSEC certificate for more than 2 decades and is having one of the largest capacity of manufacturing PLB HDPE DUCT in India.

VEEKAY PLAST is also BIS License holder for following types of Pipes:

  • IS 4984 : 2016 – Polyethylene pipe for water supply.
  • IS 14333 – High density polyethylene pipe for sewerage.
  • IS: 14151-1999 (Part I & Part II) – High density polyethylene Sprinkler System.
  • IS 16098 : 2013 (Part II) – Structured-Wall Plastics Piping Systems for Non-Pressure Drainage and Sewerage Part 2 Pipes and Fittings with Non-Smooth External Surface.
  • IS 14930 (Part I & Part II) – Conduit systems for Electrical Installations.
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