In recent years, three North American manufacturers have focused on slimmer designs of roof hatches for the school bus market in response to concerns that high-profile hatches are more likely to be damaged.
Drivers may have trouble pulling into garages when hatches are too tall. "There are many older garages in the industry with 10-foot doors, and as buses have gotten a little taller in about 15 to 20 percent of the market, it's difficult actually getting the buses through some of the garage doors," says Mark McAlpine, director of sales and marketing for Transpec Worldwide in Sterling Heights, Mich.
Another common scenario is a tree branch getting caught on a high-profile hatch. "When the bus goes through a place with low-lying tree limbs, the hatch gets damaged and operators are constantly having to replace either the whole hatch itself, or at least the dome of it," explains Paul Baczewski, school product group manager for Webasto Thermosystems in Lapeer, Mich.
While hearing the cry for lower-profile roof hatches, manufacturers are careful not to compromise the quality and stability of the hatch, as well as its primary functionality as an easily operable emergency exit.
Here's a look at some of the latest roof hatches available for the school bus market.
Specialty Mfg. in Pineville, N.C., offers five emergency escape roof hatches for the school bus market. Its newest innovation is the ProLo (Model 9245), a streamlined hatch that boasts a mere 0.75-inch height from the roof of the bus. "The OEMs came to us and said they needed a hatch that was easier to install and wouldn't leak," said Dana Spurgeon, national sales manager for Specialty. Specialty's answer was the ProLo, a vacuum-formed, contoured hatch that blends with the existing line of the bus and promotes water run-off. The hatch lid has a single sealing surface with only one gasket for superior leak resistance. The hatch is easy to install from inside the bus and does not require outside mounting holes, screws, adhesives or fasteners. The ProLo can be ordered on any new school bus.
The other four offerings from Specialty are the Standard Roof Hatch (Model 8945), the Value Hatch (Model 8645) made from ABS material, the Static Vent Roof Hatch (Model 8915) and the Fan Hatch (Model 8910).
All of Specialty's hatches are created from a specially developed, UV-stable, high-impact material. They feature a multi-position ventilator with simple one-handed emergency exit operation. The exit opening is an unobstructed 510 square inches, and the hatches meet all federal regulations. There are models available to fit all bus roof configurations, and none of the hatches require special maintenance. Hatch options include key lock, mouthing gasket, alarm, reflective tape and bilingual decals.
Transpec Worldwide has been manufacturing safety vents for more than two decades. Transpec's "firsts" include the first emergency exit hatch made for ventilation, the first roof hatch with a built-in static vent and the first hatch with an exhaust fan for greater air circulation.
All Transpec vents are virtually jam-proof, are large enough for adults, comply with government regulations and have a flow-through ventilation system.
"We are working now on designs with even lower profiles but which also maintain Transpec's high standards for material quality and product strength," says McAlpine. Model 1925 is Transpec's Low Profile Econo Vent, which the company has been manufacturing for about four years. It has the same hardware and operating mechanisms as all Transpec vents, but a lower cost.
The Model 1100 Triple Value Safety Vent includes a static exhaust vent that provides constant ventilation even when the hatch is in the closed position.
Another of Transpec's more popular vents is the Model 1600 Power Safety Vent, which features a static exhaust vent, a five-position ventilator and a power fan. The electrically operated exhaust fan circulates 650 cubic feet per minute, for increased ventilation in a single unit.
Webasto Thermosystems is a newcomer to the North American school bus hatch market, though the company has 50 years of experience manufacturing roof hatch systems globally. The company came up with the concept for the Advantage Hatch toward the end of last year after getting much feedback from the industry.
"The main complaint we heard from OEMs and body builders was that their customers didn't like hatches sticking up over a certain number of inches," says Baczewski. In response, Webasto's Advantage Hatch was built almost one inch lower than most available standard roof hatch models. The outer emergency exit handle is also flush-mounted to protect from damage caused by structures and debris. The hatch uses an injection-molded independent four-hinge system for durability in all three open positions.
"Many drivers and state directors told us the biggest problem with roof hatches is that they are difficult to re-latch," adds Baczewski. So Webasto designed an easy re-latch mechanism for its hatch - simply place the hinges in position and turn the exit handle to the lock position.
Notable safety features include a microswitch alarm that sounds when the hatch is open and reflective tape available in multiple colors to meet federal, state and local regulations. The Advantage Hatch meets FMVSS 217 and 302.