The solution for the ban on combustible materials within a cavity created by an SFS system and brickwork is this non combustible cavity tray.

SafeSeal range of trays are manufactured from non combustible stainless steel which (as stated in Commission Decision document 1996D0603-EN-12.06.2003-002.001-2) is to be considered as Class A1 without the need for testing. Therefore this fully complies with NHBC requirements and Approved Document B: Fire Safety Volume 2 and Building Regulations 7.2.



Product Features

  • A1 Fire Rated
  • Manufactured in 304 or 316 Stainless Steel
  • Shear tested by Lucideon Labs
  • Fast and Easy Installation
  • For cavities 100mm to 300mm (other sizes available)
  • Fast delivery from approval of drawings
  • Full design service

Standard Components

Standard trays are available in a range of lengths and is manufactured to suit cavities from 100mm to 300mm in increments of 25mm. Also standard are internal/external corners at 90 Degrees and left/right handed stop ends for each cavity size. Non standard sizes available upon request.

The standard trays are manufactured from stainless steel grade 304 however grade 316 is also available on request for marine envi- ronments or if a higher specification is required.

Please contact the sales team if a special cross section is required due to lintel design or due to site constraints.

Building Regulations Document B (Fire Safety) 2019 Edition 

In response to incidents involving the spread of fire within external cavities on tall buildings, the Build- ing Regulations have been updated to prohibit the use of combustible materials within the external cavities of buildings over 18m in height (soon to be 11m). The regulations apply to buildings contain- ing one or more dwellings; an institution; or a room for residential purposes (excluding any room in a hostel, hotel or boarding house, but including student accommodation, care homes, sheltered hous- ing, hospitals and dormitories in boarding schools). The amendments to the Approved Documents provide the further guidance (12.10 Note 2) that “materials achieving limited combustibility cannot be deemed to meet the requirement using an alternative classification method.”



SafeSeal is manufactured entirely from 304 Stainless Steel. Stainless Steel is recognised by the European Commission as an A1 fire rated classified material, the highest level of fire safety performance Therefore no additional testing is required to prove its non- combustible properties.

To read more about the regulation update visit:

Following Grenfell, the industry required an innovative solution to cavity fire protection and as such, Dorsey were approached by lead- ing construction and brickwork companies to produce a viable solution. Dorsey designed SafeSeal in accordance with current industry regulations .

SafeSeal A1 fire rated cavity tray was created to replace combustible cavity trays which have been restricted on all new projects us- ing an SFS system that exceeds 18m in height. (11m in Scotland) SafeSeal was designed in conjunction and advice from a range of Industry Experts and Governing Bodies. This way Dorsey could identify issues within the concept and adapt to overcome them, pro- ducing a market leading product which is fully recognised and accepted by UK warranty providers. The product is the best of its type available in the UK market.

SafeSeal is a bespoke cavity tray solution designed individually for each project and to overcome complexities within the cavity. A detailed layout drawing is supplied for approval for each individual project.

Design and Testing. SafeSeal has been designed in accordance with BS 8215:1991 ‘Design and Installation of Damp-Proof Courses in Masonry Construction’

SafeSeal satisfies the required characteristics of durability, resistance to shear and flexural stress, compatibility and pliability.

As well as complying with the combustibility requirements in the current Building (Amendment) Regulations 2018 for wall components in high-rise residential buildings over 18 metres in height, SafeSeal provides property owners with a fire-safe solution for all multi- occupancy buildings, regardless of height.

Standard Sizes for trays/ Product code ref


Supplied Lengths (mm) 3000 2500 2000 1250 1000
100mm Cavity CTA100-3-304 CTA100-2.5-304 CTA100-2-304 CTA100-1.25-304 CTA100-1-304
125mm Cavity CTA125-3-304 CTA100-2.5-304 CTA100-2-304 CTA100-1.25-304 CTA100-1-304
150mm Cavity CTA150-3-304 CTA100-2.5-304 CTA100-2-304 CTA100-1.25-304 CTA100-1-304

Ancillary Products/ Product code ref:


External Corner at 90° Internal Corner at 90° Left Hand End Profile Right Hand End Profile
100mm Cavity CTA100-EXC90-304 CTA100-INC90-304 CTA100-LEC-304 CTA100-REC-304
125mm Cavity CTA125-EXC90-304 CTA125-INC90-304 CTA125-LEC-304 CTA125-REC-304
150mm Cavity CTA150-EXC90-304 CTA150-INC90-304 CTA150-LEC-304 CTA150-REC-304


Dafa Tape

DAFA UV tape is a single-sided tape made from acrylic.

DAFA UV tape is particularly suitable for outdoor use in the building envelope during difficult working and building conditions. The tape can also be used for vapour barriers in tough climates.

DAFA UV tape can withstand direct sunlight, periodic heavy rain, moisture and large temperature fluctuations without losing its adhe- sive properties.

DAFA UV tape meets the stringent requirements in relation to per- manent airtight seals for vapour barriers in accordance with EnEV (DIN 4108-7).

Technical specifications

DAFA UV tape.

Single-sided tape with exceptional strength and adhesion, suitable for overlapping on wind barriers or difficult vapour barrier joints.

Acrylic adhesive, solvent-free and water-based. The adhesive is highly resistant to moisture and other climate effects.

Sealing Instructions

SafeSeal should be installed with a minimum 100mm overlap on all intersections.

To provide a total weather and vapour seal Dorsey recommend applying a strip of 50 mm Butyl Mastic Tape between the metal faces on the overlap, pushing the two surfaces together to achieve the bond.

It is also recommended that all overlaps and intersection with the internal structure be sealed with a continuous strip of 60mm Dafa Tape.

More Info on : 

Safeseal Moisture Barrier Tape

SafeSeal Cavity Tray