The scale is divided into 10 categories... with 1 being the lowest, and 10 being the highest.
1: Slight perp... sometimes silent. Usually detected within 30 seconds by a well trained nose. Best released by lifting one half of the arse and slowly allowing gas discharge. Usually has the smell of a warm biscuit.
2: Gas Shot... Can be heard if not carefully released, detection time is same as above. Very little Vibration if arse is firmly planted on chair / bench / sofa. Usually let off in queues, usually in Banks or where people are buying a Lottery ticket.
3: Flustered Fart... Can be heard in quieter surroundings, usually let off when walking. Never detected by its owner, but by the next poor soul who stops nearby the release site. Best dropped when walking away from a cash machine.
4: Parppp... Definitely detectable by anyone in close proximity. Higher volume output than that of the afforementioned scale factors... Can be used to show off to mates, or to be kicked out of bed by the missus. Slight vibration occurs if directly aimed onto a spring based matress.
5: Trump... Most commonly heard in working mens clubs, and changing rooms. Men find a sense in pride in dropping these, although women (other than wives married over 5 years) find this type of fart impossible to acheive in the presence of any person. Vibration can be felt on laminated flooring upto 2 metres from the epicentre.
6: Barp!... Highly flammable and detectable by all within a 5 metre radius. Requires round neck jumper to be substituted for gas mask for at least 120 seconds after the release. High level of Turdulence which can be easily felt if sharing a pub bench with the offending Barp!'er.
7: Serial Barp!... Not advised unless alone, or with person you dislike. A series of loud farts are released with no shame involved. Can lead to a spurt of bum gravy from the offenders rectum if not carefully released. Tremors from a serial barp can be felt many metres away. If dropped whilst bathing, can create high numbers of methanic bubbles and extremely obvious vibrations detectable by anyone situated in the room directly below the bathroom.
8: Bottoms Up... A fart of unprecented excellence, high in stink factor and low in shame factor. Only achievable by overweight men and lesbians. Requires offender to take a shite minutes afterwards, as the forces required to create a bottoms up fart can push faeces towards the anal opening and out into the offenders underpants. Skid marks inevitable.
9: Anal Lacerator... Highly potent, the force involved in releasing a fart of this magnitude are immense. Offenders are advised to use caution, examples could be by pulling down their clothing to avoid causing permanent material damage to their garments or wearing someone elses underwear. Painfully released and extremely high decibel count (over 80dB) and best dropped during football matches or when in a jacuzzi, although lifting of the arse is advised to avoid excessive vibration to the tile work.
10: The Ultimate in Fart Technology... This fart is only available to those who eat Mexican & Indian Cuisine. The gaseous effects of which can contaminate a room for upto 30minutes from the time of release. Causes eyes to water and throats to dry up. Offenders require dark underwear to cover up excessive stains. Vibrations of a fart of this power can cause tables and chairs to shake momentarily. Not advised during family barbecues and wedding ceremonies. Offending persons usually have homosexual tendencies or large thick stools which tend to be unflushable.
Guy 2: Mint lad... did she say owt?
Guy 1: No mate, shes not moved since.