New vertical doors would act as fire barriers in the sprawling hallways of Russell Senate Office Building and Cannon House Office Building, once and for all bringing the aging structures into compliance with fire safety code.

But those doors are only the Architect of the Capitol’s second and third priorities for fiscal 2012. Atop Architect of the Capitol Stephen Ayers’ list of the top 25 ventures he wants Congress to fund next are the final major repairs to the much-maligned utility tunnels that deliver heat and cooled air to the Capitol complex.

The utility tunnel modernization project is a priority because the AOC must finish it by June 2012 or risk violating a legal settlement agreed to in 2007 after tunnel workers publicized their concerns with the Capitol’s asbestos-filled tunnels.

Ayers said in an interview last month  the project is on schedule.

Although the AOC does not comment on pending legislation, the agency’s confidential budget justification obtained by Roll Call lays out in detail each ranked project.

To complete the utility tunnel work, the agency needs $17.4 million to repair concrete and install structural buttresses in two of the tunnels. More than $158 million has already been spent on the underground repairs.

Sixty-six projects were considered for inclusion in the fiscal 2012 budget request, but only 25 made the final cut. In sum, the AOC is requesting more than $706 million, a roughly 20 percent increase compared with its current funding.

More than $176 million of that would fund the top 25 projects. Among them are seven projects for Congressional office buildings, including the Cannon and Russell projects, ranked second and third respectively, to shore up dangerous fire hazards identified by the Office of Compliance.

The buildings’ vast hallways “result in an increased risk to the occupants of the buildings whose options and ability to evacuate the building in a safe and timely manner is compromised in the event of an emergency,” according to the AOC documents.

It’s unclear how many hallways will have extra barriers installed, but the budget request states that they will be placed in “various locations.”

The atrium skylights in the Hart Senate Office Building are leaking and are in need of repair, though that project is 16th on the list.

But the Architect is asking for $8.9 million to replace every skylight with energy-efficient, impact-resistant products, reducing the risk of water and mold damage to the building’s interior and the massive Alexander Calder sculpture in the building’s foyer.

Library of Congress facilities dominate the list with eight total projects, four of which are among the top 10.

Those include a $12 million project to construct an Americans with Disability Act-complaint access ramp at the building’s east and west entrances, as employees with disabilities “continue to have problems navigating the existing entrances with risk of injury,” according to the AOC documents. The project would also repair failing concrete on the roof of the John Adams Building garage.

The AOC also wants to install a sprinkler system in the Thomas Jefferson Building, where occupants, visitors and Library collections are “at significant risk of exposure to fire and smoke as evacuation could be impeded.”

A $2 million fire-safe secure storage room is also in the works to house some of the Library’s most precious items, making them less susceptible to theft.

Two classified security projects are listed in the Architect’s top 10. Though specifics are left out of the budget request, one would fund the first phase of a four-tiered infrastructure plan in the House and Senate garages. The other is a study into an off-site mail-delivery center.

Setup for the 2013 presidential inauguration is handled by the AOC, and the agency is asking $4.2 million to construct a stage, a specialized sound system, audience chairs, media stands and security items on the Capitol’s West Front.

The inauguration festivities rank 12th on the list, while at 13th, the Architect listed $6.7 million for repairs to the Capitol’s ornate Brumidi corridors, which have deteriorated because of pollution from open windows, tobacco and fireplace smoke and over-painting.

Including the utility tunnel project, the Capitol Power Plant would undergo three costly repairs, the other two being installation of centrifugal chillers.

Among the most costly projects is repairs to concrete slabs in House-side West Underground Garage.

“If not addressed in the immediate term, the slabs could collapse locally and cause considerable damage to life and property. If not addressed in the long term, the entire structure could collapse catastrophically,” the AOC documents said.