HVAC stands for Heating, Ventilation, and Air Conditioning. In Australian commercial construction projects, HVAC refers to the systems and equipment used for regulating and maintaining the temperature, air quality, and overall indoor environment of commercial buildings such as offices, retail spaces, hospitals, and other non-residential structures.

In Australian commercial construction projects, "Hot Dip Galvanised" (HDG) refers to a process used to protect steel or iron from corrosion. This process involves immersing the metal in a bath of molten zinc at a temperature of around 450°C (842°F). The zinc coating formed during this process provides a robust and durable layer of protection against environmental elements, significantly extending the lifespan of the metal.

In Australian commercial construction projects, a "hood" or "window hood" refers to an architectural feature designed to provide shading and protection for windows. It is typically an external element that projects outward from the building facade above a window or series of windows.

In the context of Australian commercial construction projects, "honeycombs" refer to a defect that occurs in concrete structures. This defect is characterized by voids or gaps within the concrete, resembling the appearance of a honeycomb. These voids are typically caused by improper compaction of the concrete mix, inadequate vibration during placement, or the use of a mix that is too dry.

In the context of Australian commercial construction projects, "hollow core" typically refers to hollow core slabs, which are precast concrete elements used in floor and roof construction. These slabs are characterized by continuous voids or cores running through their length. The primary purpose of these voids is to reduce the weight of the slab without significantly compromising its structural integrity.

In the context of Australian commercial construction projects, a "hoist" typically refers to a temporary lifting device used to transport materials, equipment, and sometimes personnel vertically between different levels of a construction site. Hoists are essential for efficiently moving heavy loads and facilitating construction activities in multi-story buildings. They can be powered by electricity or hydraulics and are often installed on the exterior of a building under construction.

A hipped roof is a type of roof design commonly used in Australian commercial construction projects. It is characterized by four sloping sides that meet at the top, creating a pyramid-like structure. Each side of the roof slopes downwards towards the walls of the building, and the edges are typically clad with roofing materials such as tiles, metal sheets, or shingles.

In the context of Australian commercial construction projects, a "hip" refers to a specific type of roof design. A hip roof, or hipped roof, is characterized by having all sides slope downwards towards the walls, usually with a gentle slope. This design typically has no vertical ends, and the "hip" refers to the external angle where two adjacent sloping sides of the roof meet. Hip roofs are known for their stability and durability, making them a popular choice in areas prone to high winds. They also provide better drainage compared to flat roofs, which can be advantageous in regions with significant rainfall.

In the context of Australian commercial construction projects, "heartwood" refers to the dense, inner part of a tree trunk, which is typically older and more durable than the outer layers known as sapwood. Heartwood is formed as the tree ages and the inner cells die, becoming infused with natural chemicals that can make it more resistant to decay, pests, and environmental conditions.

In Australian commercial construction projects, a header refers to a horizontal structural element that spans across the top of an opening, such as a door or window . It is a beam that disperses the structural load to the outside of the opening, providing support and stability to the surrounding structure .

In the context of bricklaying, a header can also refer to a brick laid with its short end to the face of the wall . However, in the context of commercial construction projects, the term "header" is more commonly used to describe the horizontal structural element above an opening.

Hardboard is a type of engineered wood product that is commonly used in Australian commercial construction projects. It is made from wood fibers that are compressed and bonded together using heat and pressure. Hardboard is known for its durability, versatility, and cost-effectiveness, making it a popular choice for a wide range of applications in the construction industry.

In Australian commercial construction projects, a handrail is a rail that is designed to be grasped by the hand for support and stability. It is typically installed along staircases, ramps, and other areas where there is a change in elevation, providing safety and assistance to individuals as they move up or down. Handrails are an essential component of building safety and accessibility standards, ensuring compliance with regulations such as the National Construction Code (NCC) and relevant Australian Standards, including AS 1428.1 for design for access and mobility.

A half-lapped joint is a type of joint used in Australian commercial construction projects to connect two pieces of timber or other materials together. It involves cutting a notch or 'lap' into the edge of each piece, so that they overlap when joined. This creates a strong and durable connection that can withstand significant loads and stresses.