Identify, Retain and Preserve
Identifying, retaining, and preserving visible features
of early mechanical systems that are important in defining
the overall historic character of the building, such
as radiators, vents, fans, grilles, plumbing fixtures,
switchplates, and lights.
Modern heating or cooling
devices usually add little to the interior character
of a building; but historically, radiators, for
instance, may have contributed to the interior
character by virtue of their size or shape, or
because of their specially designed bases, piping,
and decorative grillage or enclosures.
Removing or altering visible features of mechanical
systems that are important in defining the overall historic
character of the building so that, as a result, the
character is diminished.
Stabilizing deteriorated or damaged mechanical systems
as a preliminary measure, when necessary, prior to undertaking
appropriate preservation work.
Failing to stabilize a deteriorated or damaged mechanical
system until additional work is undertaken, thus allowing
further damage to occur to the historic building.
Protect and Maintain
Protecting and maintaining mechanical, plumbing,
and electrical systems and their features through cyclical
cleaning and other appropriate measures.
Preventing accelerated deterioration of mechanical
systems by providing adequate ventilation of attics,
crawlspaces, and cellars so that moisture problems are
Improving the energy efficiency of existing mechanical
systems to help reduce the need for elaborate new equipment.
Failing to provide adequate protection of materials
on a cyclical basis so that deterioration of mechanical
systems and their visible features results.
Enclosing mechanical systems in areas that are not
adequately ventilated so that deterioration of the systems
Installing unnecessary climate control systems which
can add excessive moisture to the building. This additional
moisture can either condense inside, damaging interior
surfaces, or pass through interior walls to the exterior,
potentially damaging adjacent materials as it migrates.
Repairing mechanical systems by augmenting or upgrading
system parts, such as installing new pipes and ducts;
rewiring; or adding new compressors or boilers.
Replacing a mechanical system or its functional parts
when it could be upgraded and retained.
The following work
is highlighted to indicate that it represents
the greatest degree of intervention generally
recommended within the treatment Preservation,
and should only be considered after protection,
stabilization, and repair concerns have been addressed.
Limited Replacement in Kind
Replacing in kind those visible features of
mechanical systems that are either extensively
deteriorated or are prototypes such as ceiling
fans, switchplates, radiators, grilles, or plumbing
A systematic approach, involving preservation
planning, preservation design, and a follow-up
program of monitoring and maintenance, can
ensure that new systems are successfully
added--or existing systems are suitably
upgraded--while preserving the historic
integrity of the building. Here, a return
grille is successfully screened behind the
Installing a new mechanical system if required,
so that it causes the least alteration possible
to the building.
Providing adequate structural support for
new mechanical equipment.
Installing the vertical runs of ducts, pipes,
and cables in closets, service rooms, and wall
Installing air conditioning in such a manner
that historic features are not damaged or obscured
and excessive moisture is not generated that will
accelerate deterioration of historic materials.
Installing a visible replacement feature that
does not convey the same visual appearance.
Installing a new mechanical system so that character-defining
structural or interior features are radically
changed, damaged, or destroyed.
Failing to consider the weight and design of
new mechanical equipment so that, as a result,
historic structural members or finished surfaces
are weakened or cracked.
Installing vertical runs of ducts, pipes, and
cables in places where they will obscure character-defining
Concealing mechanical equipment in walls or ceilings
in a manner that requires excessive removal of
historic building material.
Cutting through features such as masonry walls
in order to install air conditioning units.