Fall safety: stairs, ramps and barriers

The section starts with the floor. Floorings in circulation areas of buildings other than private residential, and in certain areas of the latter, must demonstrate a slip-resistance class, obtained by testing, which the section's table assigns by location: requirements grow from dry interior areas to wet interior ones, entrances, bathrooms and collective kitchens, and peak in exterior areas and pools, with an additional step when the surface is sloped.

For the budget, slip resistance is a pure example of differential cost: the flooring would exist anyway, the required class selects which flooring. The practical consequence is that the class must appear in the item's specification, because it is what the supplier prices and what the final certificate demonstrates; an estimate that says porcelain tile without saying the class leaves the performance to the luck of the chosen finish.

The second block protects against falls from height. The general rule is simple: relevant level changes require a protective barrier, and the barrier has three defined performances.

Height, measured from the possible standing line: as a general reference, around 0.90 metres for moderate drops and 1.10 metres when the possible fall exceeds six metres, measured from the step nosing on stairs. The exact values are verified in section SUA 1 of the text in force.

Configuration, designed against the most vulnerable user: in areas with children present, the barrier must not be climbable, with the lower zone resolved without footholds inviting climbing, and its openings must not allow the passage of a sphere of defined diameter, the classic 10 centimetre reference in the sensitive zone. The check is made against the actual balustrade assembly.

Strength, referred to the guardrail actions of the structural actions document: the barrier is a resistant element that is calculated, not a decorative trim, and its anchorage to the support is part of the performance. The anchorage is calculated together with the support it fixes to.

The material repertoire is wide, masonry, metal, glass, and glass deserves its own note: glass balustrades and parapets must use glass with the adequate safety performance, laminated in the usual configurations, and their justification combines section SUA 1 with the impact rules discussed below. The glass specification covers its make-up and its treatment.

Stairs concentrate the section's arithmetic. The code distinguishes restricted-use stairs, essentially inside dwellings, with more permissive rules, from general-use stairs, with fully defined geometry. The essential general-use references form any designer's mental table: treads of at least 28 centimetres, risers between 13 and 18.5 centimetres, the relationship between the two bounded by the classic formula guaranteeing a comfortable gait, flights with their number of steps limited per flight and their maximum height overcome, landings sized to the stair width, and handrails mandatory according to drop and width, at defined height and extended where the section requires.

Two application nuances avoid grief. First: the stair's width is not set by this section alone but by its coexistence with DB-SI evacuation, which may demand more; sizing is done with both tables on the table, as developed in the article on occupant evacuation. Second: curved stairs and winders have their own tread measurement rules worth verifying before falling in love with the design.

The ramps of section SUA 1 follow the regime already described for accessibility, with maximum slopes decreasing with length and defined landings; a ramp that also forms part of an accessible route meets the full regime of the article on accessibility. Car park ramps, steeper, have their specific treatment.

The section closes with a requirement that surprises whoever discovers it: the cleaning of exterior glazing in private residential buildings. Panes must be cleanable from inside or from safe positions, or the means to do so must be provided, a condition that in heavily glazed façades has real design consequences, openable sashes, and budget consequences, cradles or lifelines when there is no other way.

Although this article's title is the fall, the section coexists in the document with impact requirement SUA 2, whose most budget-relevant piece is glass: glazed surfaces in impact-risk areas, the lower zones of doors and circulation enclosures, must use glass with the required safety performance or be protected with barriers. The measurement consequence is the same as with slip resistance: the glass performance, toughened or laminated as the case may be, must appear in the item, because the price differential with ordinary glass is appreciable and the affected surfaces, in heavily glazed buildings, are large.

Within the method of the article on the cost of CTE compliance, section SUA 1 is the territory of differential cost: few new items, many items made more expensive by the required performance. The estimate that identifies those performances item by item deviates little; the one that discovers them on site pays for replaced glass and rebuilt balustrades.

The first is specifying floorings and glass without their class or performance, leaving conformity to the luck of supply. The class is stated in the item and checked when the material is delivered.

The second is measuring balustrades by linear metre without qualifying strength, anti-climb configuration and anchors, which is where the real price is played out. The item must describe the complete element, including its anchorage.

The third is sizing the stair with the SUA table alone while ignoring the evacuation one, with the ensuing redesign. Both tables apply and the more demanding one prevails.

The fourth is forgetting glazing cleaning in glazed residential façades, a discreet requirement with expensive solutions when it arrives late. The solution is decided with the façade and not after it.

The fifth is neglecting small level changes, isolated steps and interior transitions, which the section treats expressly and which are, in real accident statistics, the most treacherous. Isolated steps are resolved in the design and not on site.