Fireworks Guide: Aerial Shells & Category F4 Fireworks

Bigger fireworks intended for professional use only.

Key information

  • Category F4 is the professional category of fireworks.
  • F4 encompasses a broad range of fireworks used in professional fireworks shows by trained personal.
  • Often referred to as “industrial fireworks” by the press.
  • Not available to the public. 
  • No licence exists or can be purchased, nor any training undertaken, by members of the public that entitles them to buy F4 fireworks for home use despite peristent urban myths to the contrary.
  • Aerial shells are single, large, explosive effects that fire from a mortar tube and make up the majority of big sky effects in a professional show (pros rarely use consumer rockets).

Category F4 vs. F2 and F3

Category F2 and F3 refers to consumer fireworks, with F2 having safety distances typically between 8m and 15m, and F3 having a safety distance of 25m (and more gunpowder!).

Above this we move into professional fireworks, known as Category F4. The press have sometimes refered to these as “industrial fireworks” and the term has stuck, though this term is not used within the fireworks trade.

Category F4 fireworks cover a broad range of different items – well beyond the scope of this consumer guide – including aerial shells. These often do not have a specific safety distance and it is down to the operator to ensure safe usage (mostly at distances far greater than F3’s 25m!). Many also don’t come with a safety fuse either, with the intention of being fused together or electrically fired. This is why stolen Category F4 fireworks are so dangerous if sold to the public; any fuse on them is likely to be an instant fuse known as quickmatch.

Cat 4 Setting Up
A selection of Category F4 fireworks being set up by professionals.

The mythical Category F4 licence

It is very common for firework enthusiasts to want to move up the pyro ladder from F3 cakes and rockets to larger F4 shells and other professional fireworks. For some reason there is a persistent belief that some form of “licence” is available – either through purchasing it or through training – that enables a member of the public to legally buy F4 fireworks. This is not, and never has been, the case.

F4 fireworks are not for sale to the public under any circumstances irrespective of your level of training or experience with fireworks and no licence or course exists that would enable you to obtain them.

F4 fireworks can only be purchased – and used – by professional display operators as part of their commercial display activities. In case you’re thinking “Can I set up a firework company and buy F4 fireworks through that?” (we’ve all been there with that thought!), the answer is no. A “bonafide” professional fireworks display company as defined by suppliers of F4 would be one with licensed storage (expensive), insurance (expensive) and provable expertise and training by the industry’s BPA (British Pyrotechnists Association) body or an equivalent. So professional fireworks really are off-limits to the public.

Aerial shells

Although F4 covers too broad a range of fireworks for this consumer guide, it is worth mentioning aerial shells, a common Category F4 firework.

Shells are ball or cylinder shaped fireworks which detonate in the air with one big bang and an ejection of effects. They are launched from a mortar tube by a detonation of their attached lifting charge. Ranging in size from a few inches in diameter to around 16 inches (though changes in the industry in recent years means that 7 inches is typically the largest that it is practical for most operators to store and use), they form the majority of aerial effects you’ll see in a professional show, above and beyond cakes and candles.

Aerial shell selection
A selection of loose shells before loading into tubes.
Aerial shell in tube
View down into a shell loaded into its mortar tube with the instant fuse coming out.

Most professionals don’t use rockets (like the consumer rockets you can buy for home displays) because shells, despite their bigger explosive payloads, are considered safer. This is because little or no fall out is produced by a shell (unlike a falling stick from a consumer rocket), they are more predictable in flight and they are less affected by the wind.

This begs the question, why do consumers have to use rockets with big sticks if shells produce virtually no fall out? Well there was a point in the late nineties and earlier when aerial shells were legal for the public to buy in the UK. However a couple of fatal accidents involving the public resulted in a ban.

The danger with shells in the public’s hands is that you have a projectile which could weigh several kilograms being fired from a tube at several hundred miles an hour. Being hit by that alone could be fatal should your head be over the tube. This is simply not a firework that can be sold to anyone because without sufficient training they’re potentially lethal as sadly some accidents in the 1990s proved.

These dangers simply do not exist with consumer rockets, even ones containing a small aerial shell as the effect. Even if a consumer rocket gets stuck in the tube and blows up there, you’ll still have a warning delay of the fuse burn time plus the rocket flight time combined (usually enough time to run!).

Whether there should have been a compromise – with small shells say up to a few inches being legal for consumers – is still hotly debated by firework enthusiasts in my Fireworks Forum. 

Further information and next steps

If you are following the Beginner’s Guides then you can click here to return to that page. Alternatively you can click here to see the main menu of each firework type in this section if you want to read more (or click on the menu at the top of this page to access all of my guides).

If you have any questions then please feel free to join my Fireworks Forum and ask away. Members are always here to help beginners and no question is too silly.

If you’re ready to buy fireworks for your display then the Buying Fireworks section will guide you further.