PROTECTION OF OPENINGS IN CONGESTED DISTRICTS. 123 
the sheet of steel is itself in position. By providing a pocket in the 
masonry just above the window head and making these shutters in 
three or four parts, overlapping and interlocking at the overlap, the 
whole shutter could be slid up into the wall practically out of sight. 
This arrangement would necessitate window openings slightly lower 
than those used in many commercial buildings, but the loss of light 
would not be very serious. The metal shutters when closed should 
overlap the window opening in all directions by at least 6 inches. 
This overlapping could be accomplished at the sill without making a 
pocket to catch water and dust, by forming a step in the sill itself. 
2. The windows should be made entirely of wire glass, with sheet 
metal or metal-covered sash, hung in metal or metal-covered frames. 
Clear wire glass can be used if desired. 
3. On the inside of the Avindow there should be a sliding shutter, 
either of wood covered with sheet metal or of sheet metal such as 
that described for the outside. If the outer wall is furred, a pocket 
could be made between the furring and the Avail, so that the inside 
shutters could be slid sidewise. 
It is probable that under a fairly bad exposure to fire the outer 
shutters here described Avould be so damaged that they Avould have 
to be removed. In a conflagration they would probably be Avarped 
to such an extent as to let the heat in, and possibly to soften the Avire 
glass and damage the Avindows themselves, so that they also might 
have to be reneAved— at least so far as the sash were concerned. But 
it is very doubtful if any conflagration Avould ever get through the 
sash, much less through the inside shutters. Any damage to the 
window protection, hoAvever, Avould be a A T ery small matter compared 
with the total destruction of the contents of the building and a 
damage of G5 to 80 per cent to the building itself. 
WindoAv protection of the kind just described could be so designed 
that it would not be objectionable even on the principal fronts of 
buildings. The San Francisco and Baltimore fires have demon- 
strated that all the exterior openings of eA T en fireproof buildings need 
protection. It Avould seem that the time has arrived when building 
ordinances should require it. 
If to the triple window protection described above a window 
sprinkler with adequate Avater supply is added, a defense which 
will probably not only bo adequate for its purpose, but Avhich will 
suffer small damage itself, will be provided. This system of protec- 
tion, Avhile it has never been applied, can be applied at a cost which 
is not prohibitive, especially if unnecessary and expensive finish is 
omitted. 
Practically all the fireproof buildings in San Francisco were un- 
shuttered. Many nonfireproof buildings were partially shuttered, 
but no building, except that of the Pacific States Telephone and Tele- 
