As experts in noise reduction solutions and designs, we can refer to a host of successfully completed commissions and products. Here is a small selection of the solutions we have created over the years in partnership with our customers.

Gas turbine installations

HIAK has been supplying acoustic and air-filtration products for gas turbines for more than 50 years. Our range includes exhaust systems, air intake systems with filtering, enclosures, ventilation units and more besides.

We supply solutions and designs adapted to different turbine types, as well as for all kinds of installation environments: onshore, offshore, desert, Arctic climate and so on. In addition to new installations all over the world, we handle condition inspections, renovations and upgrades of existing facilities.

Machine enclosures

We create bespoke enclosure solutions for all types of machines. Using our flexible construction system, we can adapt our solution to match your individual conditions with regard to size, accessibility, safety and – in particular – noise reduction requirements. We carefully examine the conditions applicable to each project and provide a performance guarantee for your peace of mind.

Our construction system can also accommodate sound walls, both mobile and fixed. Premises and manufacturing models are changing all the time, which is why it is important to ensure that wall systems are flexible and can be dismantled and reused. Of course, our systems fully live up to such requirements.


HIAK possesses experience in industrial silencers that is second to none in the industry. We tailor our silencers to meet customer requirements for noise reduction, pressure drop, materials, etc. and we are happy to provide a performance guarantee.

We deliver all kinds of silencer, where the final choice is defined by the customer’s specific needs. Our unique rod silencers are an excellent choice for many installations. They feature a number of advantageous properties such as compact and light design, good thermal/flow properties, and the option of replacing or cleaning the silencer body.

The most common applications for our silencers include:

  • Steam evacuation from safety, blow out and starting steam valves. We supply both purely absorptive silencers and motor pressure silencers. For emissions that vary in flow, absorptive silencers ensure more secure performance. For steam silencers, we use our splitter technology, which ensures a long service life in spite of the rapid temperature increases involved.
  • Flue gases from flue gas fans, where we optimise the silencers for low pressure drop so as to ensure constant performance. We can also supply cleanable silencers, which reduce the risk of declining performance over time.
  • Combustion air or exhaust gases from gas turbines or engines. High temperatures, turbulent flows and major variations in pressure are just some of the criteria that apply in these environments. Our silencers are designed to handle tough conditions, and we can present reference projects from installation environments of all kinds.
  • Process air from heat recovery, ventilation, etc. are typical silencer installation areas in paper and pulp mills, energy plants, mines and process industry facilities. We have the products to create complete solutions for all aspects of noise elimination projects.
  • Oxygen evacuation demands silencers with an elevated level of purity – and we have the solutions.
NonSonus Fresh air valve

Noise damping fresh air wall vent NonSonus FLV 65.

HIAK’s fresh air valve NonSonus FLV 65  is a highly effective noise damping valve. It is unique as it dampens noise better than any other fresh air valve on the market. The valve has a 65 dB reduction value (Dn,e,w) for a wall thickness of 400mm.

The fresh air valve has been tested by an accredited laboratory, RISE AB, according to the latest standards EN ISO 10140-2 and EN 13141-1.

Wall thickness         Dn, e, w           Airflow
200 mm                    57 dB                 7 l/s
400 mm                    65 dB                 7.4 l/s

Reference area 10m², fully open valve, at Δp pressure differential 10 Pa.

The delivery of NonSonus FLV 65 wall vent will begin in early 2019.
More info later on this page.

Soundproof doors

Doors from Hedemoradörren meet the highest acoustic requirements. A well-insulated wall must be fitted with the right type of door if you want to keep the noise out. Installing a Hedemoradörren door is the most efficient way to ensure the undisturbed ambience that is essential during a theatrical performance, a concert or a meeting. And we always supply a sound guarantee on all our soundproof doors.

For details, see

Sound enclosures for transformers and reactors

These sources typically produce tonal, low-frequency noise that is perceived as intrusive and unpleasant even at low levels. Noise reduction measures are a tough challenge, and solutions have to be specially designed to generate the desired effect and appropriate function. For such applications, we have developed a range of products with different properties to ensure optimal acoustic results and live up to other functional requirements. The development work has taken place over many years and in partnership with leading suppliers of power distribution facilities.

Our project range is intended for suppliers and for facility owners that need to upgrade existing installations in order to reduce environmental disruptions.

Control rooms and production offices

We build bespoke control rooms and production offices to live up to the highest demands for comfort, design and accessibility. Controlling and monitoring machines in a noisy environment requires a properly soundproofed, ergonomic and secure control room. Making sure the external physical setting allows operators to make the right assessments and take the right decisions is quite simply crucial to safe, efficient production.

We supply turnkey solutions with built-in ventilation, cooling, electrical connections, control room desks, kitchen facilities, etc. and assist with project planning including noise and vibration measurements.