PROJECT DIRECTIVE # FOR KALISPELL PUBLIC SCHOOLS

Transcription

1 PROJECT DIRECTIVE # FOR KALISPELL PUBLIC SCHOOLS GLACIER HIGH SCHOOL SITE INVESTIGATION SECOND FLOOR CLASSROOM PODS INSULATION AND VAPOR BARRIER INSPECTION TECHNICAL MEMORANDUM NO. 1.1 April 1, 2011 Prepared by: 125 Schoolhouse Loop Kalispell, Montana

2 1.1.1 INTRODUCTION In the mid-afternoon of February 26 th, 2011, Kalispell Fire Department responded to a fire alarm signal at Glacier High School. This alarm turned out to be the result of a tripped flow-sensor which is part of the building s automatic fire sprinkler system. Flowing water in the building s fire sprinkler piping system was found to be due to a burst fire sprinkler pipe in the acoustical ceiling space above room B211 in classroom Pod B. Flowing water from the broken pipe caused extensive damage to the facilities 1 st and 2 nd floor interiors. Morrision-Maierle, Inc. was contracted by the Kalispell School District to inspect the existing construction conditions of the 2 nd floor ceiling systems, identify the cause of the broken pipe, and determine other areas of construction that may be of concern. At the time of the inspections, most of the building s interior finishes had been completely repaired. 1

3 1.1.2 INSPECTION OF EXISTING CONDITIONS On March 22 nd, 25 th and 30 th, 2011, Morrision-Maierle was on site at Glacier High School to observe the existing conditions of the facility as pertains to the second floor insulation and vapor-barrier assemblies. These construction systems became the subject of concern after the recent water damage from the frozen sprinkler pipe. Multiple areas of the second floor ceiling and attic above were inspected including the rooms: A215, B211, D215, and E11 as well as stairwells A1, B1, D1 and E1. Upon removing the acoustical, lay-in ceiling panels from rooms A215, B211, D215, and E11, the following condition could be observed. Refer to Pictures #1 and #2. In this photograph it can be seen that there are exposed structural, wide-flanged beams. The significance of this is that there are numerous air-gaps around the beams which allow the infiltration of ambient, and potentially frigid air, from entering into the acoustical ceiling space from the adjacent, vented soffit. During the March 30 th inspection there was an outdoor wind condition strong enough to demonstrate the resultant effect of these construction gaps. Air movement could be felt, especially in the corner of the ceiling where the beams make a bolted connection to another framing member. This condition can be observed at rooms: A215, D215, and E211. Room B211 had already been modified by the addition of vapor barrier with the reconstruction of that area after the water-damage from the burst pipe. Refer to Picture #3. Picture #1 Picture #2 Picture #3 Picture #4 2

4 Inspection of the insulation in the attic spaces directly above rooms A215, B211, D215 and E211 revealed the following condition: 3.5-inchs of fiberglass batt insulation resting on top of the gypsum board ceiling with no ceiling vapor barrier. Refer to Picture #4. One exception to the previously described attic insulation condition was observed in the area directly above room E211. This area has 10-in insulation batts applied between the roof s rafters in the cold attic. Given that this arrangement provides no net thermal insulation value to the conditioned space below, it can be speculated that the batting was mistakenly applied. Refer to Picture #5. This arrangement was also observed in the attic areas above stairwells D1 and E1. Although the rafter insulation provides no positive thermal insulating benefit, it is not believed to have any negative effects and therefore does not need to be removed. It should be noted that the areas in question, that is, the areas above A215, B211, D215, E211, A1, B1, D1 and E1 have been constructed in a different manner than the adjacent ceilings. It can be seen from Picture #6 that all other ceiling areas above the 4 classroom pods have been insulated with 10-inches of loose fill insulation and are sealed with vapor barrier which has been properly taped to the rafter blocking or steel framing. Picture #5 Picture #6 3

5 1.1.3 FACILITY CONSTRUCTION DRAWINGS AND DETAILS The area where burst pipe occurred is above the small teacher s room, B211. Refer to Figure 1. Figure 1 Partial View of Architectural Plan, D West Classroom Wing, Second Floor, Sheet A111 Wall Section 2, Sheet A304 References the construction detail shown in Figures 2 and 3. These details show a continuous, 6-MIL vapor barrier immediately behind the wall and ceiling assemblies. This cross sectional detail is typical for the classroom pod areas where the broken pipe occurred. 4

6 Figure 2 Partial View of Architectural Wall Section #3, Sheet A313 Figure 3 Architectural Wall Type A, Sheet A100 5

7 Figure 4, (below) references the roof construction drawing A113. This roof plan is typical for the four classroom pods. Detail 7, A114 references the exterior wall and roof construction. Refer to Figure 5. Figure 4 Partial View of Architectural Roof Plan, Detail #3, Sheet A113 6

8 Figure 5, (below) references construction drawing detail 7, A114 which shows the adjoining of exterior wall and roof systems at each of the building s four similar classroom pods. This detail is referenced from architectural roof plan A113. The plan calls for this detail to be applied at two distinct locations; the mechanical penthouse, and the soffit end of the pitched roof above the classrooms. Refer to Figure 4. This detail identifies vapor retarder to be installed in the wall and roof system immediately on the interior side of the batt insulation. The vapor barrier, shown in the detail, is to run continuous between the wall and roof system. Insulation batts for the ceiling have been specified as 6 thick. Wall insulation, although no thickness has been identified in this detail, is shown to fill the entire exterior wall framing cavities, which is 6 thick. Detail 7, A114 (Figure 5) shows a pitched ceiling attached to the bottom of steel rafters with batt roof insulation. This arrangement applies to the mechanical penthouses and not above the classroom pod areas as suggested by detail 3, A113 (Figure 4). The classroom areas are constructed with a trussed steel roof system, a cold attic, a horizontal ceiling and 10 of loose fill insulation. Refer to Picture #6. Figure 5 Architectural Detail #7, Sheet A114 7

9 Figure 6, (below) references construction drawing detail 7, S210 which shows the structural framing in the areas above the classroom pods. This detail shows the wide-flange steel beam and the interconnected exterior curtain wall. The steel beam shown in this detail is typical of the beams referenced in the Inspection of Existing Conditions section of this technical memorandum. Refer also to Pictures #1 and #2. Figure 6 Structural Detail #7, Sheet S210 8

10 1.1.4 FACILITY CONSTRUCTION INSULATION & VAPOR BARRIER SPECIFICATIONS Figure 7 references a portion of the original construction specifications for the building s thermal and vapor barrier systems. SECTION BUILDING INSULATION PART 2 PRODUCTS 2.4 VAPOR RETARDERS A. Polyethylene Vapor Retarders: ASTM D 4397, 6 mils thick, with maximum permeance rating of 0.13 perm. B. Vapor-Retarder Tape: Pressure-sensitive tape of type recommended by vapor-retarder manufacturer for sealing joints and penetrations in vapor retarder. C. Vapor-Retarder Fasteners: Pancake-head, self-tapping steel drill screws; with fender washers. D. Single-Component Nonsag Urethane Sealant: ASTM C 920, Type I, Grade NS, Class 25, Use NT related to exposure, and Use O related to vapor-barrier-related substrates. PART 3 EXECUTION 3.4 INSTALLATION OF VAPOR RETARDERS A. General: Extend vapor retarder to extremities of areas to be protected from vapor transmission. Secure in place with adhesives or other anchorage system as indicated. Extend vapor retarder to cover miscellaneous voids in insulated substrates, including those filled with loose-fiber insulation. B. Seal vertical joints in vapor retarders over framing by lapping not less than two wall studs. Fasten vapor retarders to wood framing at top, end, and bottom edges; at perimeter of wall openings; and at lap joints. Space fasteners 16 inches o.c. C. Firmly attach vapor retarders to metal framing and solid substrates with vapor-retarder fasteners as recommended by vapor-retarder manufacturer. D. Seal joints caused by pipes, conduits, electrical boxes, and similar items penetrating vapor retarders with vapor-retarder tape to create an airtight seal between penetrating objects and vapor retarder. E. Repair tears or punctures in vapor retarders immediately before concealment by other work. Cover with vapor-retarder tape or another layer of vapor retarder. Figure 7 Construction Specification Section Building Insulation 9

11 1.1.5 EVALUATION OF TEMPERATURE DATA The building s automatic HVAC temperature control system recorded data from various air-handling unit s return air plenums around the time of the burst pipe on February 26 th, This data showed that the temperature of the air returning to air-handler AHU SW2B B Pod had reached a recorded low of 44.7 F at 12:46 AM. This low temperature occurred in the early morning hours before the burst of the sprinkler pipe in the mid-afternoon. This unusually low temperature suggests the presence of outdoor air infiltration into one or more areas served by this air-handler. Table #1: Air-handler, AHU SW2B Temperature Log Date Time AHU- AHU-SW2B OSA Temp SW2B Dish. Temp Return SW2B Air Return Temp Air Temp 26-Feb-11 1:16:33 PM Feb-11 12:46:33 PM Feb-11 12:16:33 PM Feb-11 11:46:33 AM Feb-11 11:16:33 AM Feb-11 10:46:33 AM Feb-11 10:16:34 AM Feb-11 9:46:34 AM Feb-11 9:16:34 AM Feb-11 8:46:35 AM Feb-11 8:16:36 AM Feb-11 7:46:37 AM Feb-11 7:16:38 AM Feb-11 6:46:39 AM Feb-11 6:16:40 AM Feb-11 5:46:40 AM Feb-11 5:16:42 AM Feb-11 4:46:41 AM Feb-11 4:16:41 AM Feb-11 3:46:41 AM Feb-11 3:16:41 AM Feb-11 2:46:41 AM Feb-11 2:16:41 AM Feb-11 1:46:42 AM Feb-11 1:16:42 AM Feb-11 12:46:42 AM Feb-11 12:16:42 AM

12 1.1.6 SUMMARY, CONCLUSION AND RECOMMENDATONS The burst sprinkler piping which occurred on February 26 th, 2011 above the dropped ceiling system in room B211 is the result of brittle fracture due to freezing of the water in the pipe and subsequent thermal expansion. The most probable cause of the freezing condition which created this situation was wind-pressurized, cold air infiltrating into the ceiling space by means of open gaps in construction. These construction gaps can be observed where the structural, wide-flanged beams that support the roof trusses protrude through the gypsum board exterior wall and ceiling corners. In particular, the large gap at the bolted beam connection. Refer to Pictures #1 and #2. These construction gaps have been observed at 4 locations throughout the facility. The locations of these gaps occur at the exterior wall/ceiling above the following rooms: A215, D215, E211 and previously above B211. It is recommended that these construction gaps be immediately sealed airtight to prevent a repeat of the February 26 th freezing event. The suggested method of sealing these construction gaps is by application of a continuous vapor barrier which would bridge the gap between the wall and ceiling by wrapping the steel beam with the vapor barrier on the interior side. It is recommended that this vapor barrier be extended to interconnect with the existing wall vapor barrier while continuing into the attic above and immediately on the interior warm side of the ceiling insulation. All new vapor barrier should be of type identified in and installed per Architect s construction specification section Refer to Figure 7. The construction gap above the ceiling in room B211 has already been remediated with the reconstruction of that area after the water-damage from the burst pipe. The construction gaps above this area have been sealed by vapor barrier between the wall and ceiling and wrap the steel beam as previously mentioned. It is also recommended that the ceiling insulation in the attic space above the rooms: A215, B211, D215, E211 as well as stairwells A1, B1, D1 and E1 be increased from the current 3.5-in of batt insulation to a full 10-in. As previously mentioned, a vapor barrier was specified and should be installed in the attic on the underside of the ceiling insulation (top of gypsum board) to prevent ambient air from penetrating into the ceiling space below. Currently, there is no vapor barrier installed above the 8 aforementioned areas. This vapor barrier will need to be installed prior to the addition of new ceiling insulation. 11