The fire safety system employed in a multi-story structure is straightforward; the fire department connects to an access panel on the outside via hoses and pumps the water into the system's dry riser. More often than not, this works as intended. But even less frequently do emergencies pan out like the ideal scenario.
Access blocked, streets littered with debris, the perfect spot to connect to the inlet is rendered completely inaccessible. Dual-access fire inlets are helpful in these situations to provide a backup for when things seem too good to be true in terms of access to water supply.
Why Single Access Is a Compromised Access Point
One of the most common configurations in a structure is a single inlet access point where a fire department connects with their hoses to establish a supply line into the system's dry riser. But this makes sense when everything goes according to plan. Fires create chaos.
People park in front of connections (sometimes across the street immediately after the fire alarm sounds because they don't think anything has happened), sometimes people crash vehicles into buildings making access from one side of a structure to the other impossible. In snowy, winter climates, snow piles, and even ice build-up makes proper access an impediment that takes time for crews to clear.
Street access is another area of concern. Some structures are too close to one-way streets or narrow roads and the fire truck can only approach from one direction. If that direction also happens to be aligned with the inlet access point, then great. But if not, crews are forced to drag hoses farther than necessary, decreasing water pressure and increasing stress.
How Two-Way Configuration Affects Access Options
A 2 way breech inlet dry riser door provides connection access for two separate angles; either two adjacent sides of the structure or oppositional sides. When the fire apparatus can't access a designated connection point, yet there's another available, crews take the time without having to redirect or readjust the fire truck in potentially tight spaces.
Two-Way connections also recognize that fires occur, ironically, without considerations for building architecture. If a fire is raging on the north side of a structure, the north access point could be dangerous with flames, smoke, and debris. But if there's also southern access, crews can establish water supply without being as exposed while still being able to service the entire riser because water does not care which panel it enters; it travels through risers on each floor.
The Important Difference When Responding to Major Incidents
The major building fires bring multiple fire companies together. Each company is equipped with its own hoses, connects, and personnel, sometimes entry points get established faster than anticipated but hoses need to be set up so no one should be walking over someone else's line trying to gain access.
Dual access allows different companies from various perimeters to connect. One team connects at one point while another establishes backup supply from within. Should one connection fail (equipment issues, broken connections, failing pressure) water flows from another stable inlet. Systems should never rely on establishing perfect connections at one access point.
Installation Factors That Matter
Adding an inlet where two are now present is not as simple as adding another door on a separate wall. The entire riser system must have valves set so that either way works without contamination or pressure loss from one area to another. Many older systems did not accommodate dual access with only one inlet but can be retrofitted if there's enough piping space and proper ideal valve placements.
In newer building designs, angle plays a difference in where best to situate secondary inlets, such as on corners where the fire engine can come more cleanly from perpendicular roads (rather than single lane roads). Sometimes the secondary inlet may be best accessed through a service alley, parking lot or courtyard, wherever can keep fire trucks out of the way of major traffic flow.
The doors also need protecting for weather exposure, unnecessary human exposure, and potential accidents. Outside access at ground level is particularly vulnerable to being hit by vehicles loading and unloading and gets worn away quickly. Proper construction depths and reserves enable these access points to have longevity where they're functional for decades - not just a couple of years once installed.
Code Guidelines vs. Real-Life Usefulness
Certain codes in buildings over a certain number of height or occupancy type stipulate dual access connected systems as code; this assumption acts on the practical sense that more complex situations require avenues for backup options. But even those that don't require two-way connections are better with them.
The price difference between single and dual access in new construction does not vary overwhelmingly (materials and labor mainly). It's retrofitting that exposes higher costs where existing systems are already set in place but it's worth it for new owners wanting quality assurance against any possible variations based on site characteristics that would impede access.
Dangers When There's No Dual Access
Whatever conditions exist when there is only one inlet access are what will happen during challenging incidents. Crews find longer hose lays, they angle up at strange positions, they rely on internal standpipe systems (often only 250 gallons) for inadequate coverage instead of creating supply lines with external materials; this works but also takes additional time for critical incidents where time is crucial.
Some building managers deem the single sided inlet placement appropriate enough as it's facing the main street with clear access under normal circumstances. But this misses the point that emergencies are anything but ideal circumstances.
Making Decisions About Access Points
Building owners and facility managers should consider ideal access from a worst-case scenario, as if blocked on each side where something remains inaccessible, and how limited access on each side will create safety hazards down the line. Considerations must also be weighed through temperature changes (snow clearance) and parking patterns that could create temporarily blocked efforts.
When new, it's easier to place dual-access supports in systems that align with one another through new construction conventions. When they're existing structures it's better to weigh retrofit costs against specific vulnerabilities that exist in properties based on placement of buildings and surrounding streets.
It's not about perfection; it's about having reasonable options when Plan A doesn't work. Fire safety functions with multiple layers of protection and dual-access supports facilitate another level of security when things inevitably get messy. It may go unused for years but when it matters, it matters.
