Frequently asked questions

To help our customers about  Hawke HTS.

Alternatively the answers to frequently asked questions are also available to view.

More information about our products:


Feel free to contact us for any further information.

What is the difference between marine and civil frames?

The marine frames are made from 10mm steel bar and are typically welded into steel bulkheads and deckheads. There are different types of marine frames available.

The civil frames are made from 60 x 60 x 6 mm angle which provides a 60mm flange and are either cast into or bolted onto concrete, blockwork or brick walls and floors. Both types are available in multiple apertures. 

Choose the correct frame type e.g HMX for marine, HCX for civil



The cables are already installed – What is the solution?

If already installed, an open frame is needed e.g. HCOX2 or HMOX2. 

Note: for multiple aperture frames, the removable end can be either horizontal or vertical or both depending on the site requirements. 

However, for frames that are HCOX8+8+8x3 for example, the central aperture cannot accommodate existing cables. The removable ends must be clearly identified when placing an order.

What are the frames made of?

Frames are available as standard items in mild steel, stainless steel and aluminium.


1. Aluminium frames when installed in fire rated partitions should be fully insulated.
2. Steel frames can be coated or plated to enhance protection against various corrosive environments.
3. Specialist grades of steels are available to special order.

What frame size is needed?

A Frame required to suit a specific number of cables/pipes. The following information on cables/pipes is needed:

1. Number of cables/pipes.
2.Outside diameter of each item.
3.What percentage of spare capacity is needed for future use.

A frame required to suit a specific opening/aperture. Aperture dimensions required. (See overall frame chart in Transit manual).

How are the spaces filled where there are no cables?

The blank filler blocks are available in all module sizes and must be used to fill up the transit aperture. The application is for water or gas where the pressure is expected to be in excess of 3.5 bar. Is the specification the same?

No – applications in excess of 3.5 bar pressure require the following:

1. Heavy duty stayplates must be used – code 931P.
2. An additional 120 x 60 x 5mm packing strip (HF50) must be installed to increase compression beyond normal requirement.

How are the civil frames face fixed onto the wall or floor?

1. Hole dimensions need to be correctly sized – see frame dimension chart in Transit manual.

Note that if the aperture is to be turned inwards an additional 6mm is to be added to both dimensions to take into account the radius curve of the weld.

2. Hawke intumescent mastic is required to seal between the frame flange and the brick/concrete face. See Transit manual for application details.

How much mastic is needed to seal between the frame flange and the brick/concrete face?

One 330ml tube of mastic is sufficient to seal 3 individual frames or a multiple frame of up to 4 apertures.

The transit frames will be cast in during construction, how can the hole be kept open?

Polystyrene moulds are available to maintain the aperture. Details of wall/floor thickness needed to provide correct size.

How can the non-transit side be framed out to provide a neat finish?

A backing plate can be provided. The thickness of wall/floor is needed to provide correct size.

How can cables which are in a plastic duct be sealed?

The HRTO circular frames are designed to fit into 30mm, 40mm, 50mm, 70mm, 100mm, 125mm, 150mm and 200mm I/D pipes - See transit manual for tolerance details.

It should be noted that when HRTOs are used in conjuntion with plastic piping the product is converted to an environmental gas,water seal only.

HRTO circular frames

What are the HRTO Transits made of?

HRTO's (Hawke Round Transits) are a series of circular rubber components, each of which has a central core manufactured to accommodate one or more cables secured by the installation of corresponding Hawke Transit System Insert blocks.

The unit is fitted with compression plates at front and back. (Compression plates are available in mild steel as standard or stainless steel for corrosive environments. They are not available in Aluminium).

HRTo Hawke Round Transit

What size transits are available?

There are four standard aperture sizes and each transit frame is made up of one or more apertures. The four standard sizes are as follow. 

Size 2   60mm x 120mm installation area. 
Size 4 120mm x 120mm installation area. 
Size 6 180mm x 120mm installation area. 
Size 8 240mm x 120mm installation area. 

Each aperture has a further area of 40mm x 120mm which is use purely to accommodate the installation of the compression system. For items in excess of 100mm O/D the HCLX civil frames are available and will seal items up to 330mm O/D – see Transit manual. 

Note: HCLX frames are designed for a single penetrating item only and no stayplates are needed or available for this type of frame.

Which size block do I need?

This depends on the overall diameter of the cable or pipe. The tolerant blocks are supplied in pairs. The table in the transit manual lists the module, block sizes and colour coding for items ranging from 3mm to 100mm.

Why are the block halves coloured?

Colour coding is supplied to ensure that the correct cable insert block has been selected and installed. The Hawke colour coding is a proven inspection aid. Invaluable in verification of correct installation.

Why is lubricant used and how much is needed?

Silicone lubricant is used as an installation aid. At installation lubricant is smeared onto the inside of the frames and on all surfaces of the blocks to prevent binding of rubber components in the close tolerance installation. The silicone doesn’t harden and also assists future disassembly should modification be required. It should be noted that Hawke 967 Lubricant is not an adhesive-. One tube of lubricant is sufficient for 3 x size 8 apertures.


What are the stayplates for?

The Stayplate ensures that each complete row of filler/insert blocks is held in position during assembly and cannot be dislodged by weight of cable.

A stayplate is located above each complete evenly packed row of filler/insert blocks and once systems is under compression the stayplate retains the filler/insert blocks when under force from water/blast pressure.

Please note it is not necessary to insert a stayplate on the final row of filler/insert blocks.

Can pipes over 100mm be sealed in the transit system?

Yes – see the HCLX frames in the Transit manual. The blocks will be individually manufactured to suit the item.

Can plastic pipes be sealed in a transit system?

Plastic pipes can be sealed within a transit seal when the assembly is used as an environmental seal, offering protection against gases and liquids at pressure also acting as a barrier against sound and pests. Special assemblies are available that offer a level of fire resistance, please contact HTS for further information.

Can the installation be checked to see that it is correct?

The Hawke system is fully inspectable due to: 

The tolerant blocks seal a range of cable sizes with no modification needed by the installer. The blocks are colour coded to ensure the correct halves are put together. 

The pins in the endpacker ensure that the system is correctly compressed and the measurement of the end packer exposed thread to 10mm ensures that the endpacker has been tightened correctly ensuring the endpacker itself is completely sealed.

Feel free to contact us for any further information.