METHOD STATEMENT FOR PUBLIC ADDRESS SYSTEM

METHOD STATEMENT FOR PUBLIC ADDRESS SYSTEM 

A method statement is a document that describes how to do a task safely. You can think of a method statement like a set of instructions or a plan for the work. Method statements are also known as safe systems of work, safe work method statements or SWMS for short. This method statement details the method of installation of Public Address System. IS 1882 (1993) can help us to understand as per Indian board. We analyse with two points 1. Installation & 2. Testing & Commissioning.

INSTALLATION

1. Material under PAS

1.1 All materials shall be as per approved material submittals.

1.2 Type of cable shall be as per approved shop drawings / system manufacturer’s recommendation.

1.3 Type of Speakers shall be as per approved shop drawing / system manufacturer’s recommendation.

1.4 Type of Amplifier / Controller shall be as per approved shop drawing / system manufacturer’s recommendation

2. Applicable Location

2.1 Indoor or outdoor open or closed Public Areas, Meeting rooms, Lobby, Workstations, Rest Room, Exit staircase etc.

2.2 Need to check direction or velocity of wind / Air flow, trees at boundary, ambient noise level at different place.

3. Storage of Product

3.1 All materials received at site shall be inspected and ensured against approved material submittal.

3.2 Any discrepancies, damages etc. shall be notified immediately for further action.

3.3 Material found not suitable for the project are to be removed from site immediately.

3.4 Speaker cables shall be stored with the factory packing on the flat surface.

3.5 Materials shall be stacked properly as per manufacturer’s recommendation and covered to prevent dust and water / moisture.

3.6 Public Address Equipment to be stored as per manufactures recommendation mentioned / marked in the packing.

3.7 Ambient condition of the storage place to be as per manufacturer’s recommendation.

4. Installation of Speaker Cable

4.1 Ensure the relevant current / approved shop drawings are available with installation team.
4.2 Transfer the cable to the work place with the help manpower..
4.3 Check the cable drum for any external damage during transportation and ensure the type of cable against area of usage / application.
4.4 Type of the cable is as per approved shop drawings.
4.5 In concealed application pull Speaker cable manually through conduit installed as per approved shop drawings and approved method statements.
4.6 Leave enough length of cable at both ends of panel and devices for termination.
4.7 No through joints is allowed without the sanction of the Consultants.

5. Public Address Equipment’s

5.1 Ensure the relevant current / approved shop drawings are available with installation team.

5.2 Transfer the equipment to the work place with the help of manpower.

5.3 Location of the panel to be as per approved shop drawing after coordinating with other services.

5.4 Fixing holes will be marked properly keeping back box of the panel in place.

5.5 Fix back box properly and fix remaining panel accessories.

6. Installation of SPEAKERS

6.1 Ensure the relevant current / approved shop drawings are available with installation team.

6.2 Exact location of the device to be as per approved reflected ceiling plan for surface / recessed installation

6.3 For the Speakers, which needs to be fixed on the false ceiling, fix junction box of the camera above false ceiling.

6.4 Install the Speakers and terminate the cable properly.

7. Records

7.1 Fill QC Installation Check List duly signed-off by Site in Charge / Consultant
7.2 Inspection request duly signed-off by Sight in Charge / Consultant.

Testing and commissioning

8. Method

Find / connect the manufacturer representative’s detailed method statement and test formats for testing and commissioning of Public Address System covering the mechanical checks, switching ON the unit. Must be calculate speaker load and amplifier load before switching ON the unit and Programming and testing.

The whole system will be commissioned and certified by the manufacturer’s representative or certified persons before handing over.

9. Records

9.1 Commissioning procedure with test results should attached
9.2 Inspection request duly signed-off by Consultant should attached
9.3 Certification of installation by manufacturer’s authorised / certified representative.

10. Attachment

10.1 Manufacturer’s representative method statement detailing the pre-commissioning and commissioning procedures, including test formats.
10.2 Escalation matrix or after sales service complete Name with number.
10.3 User Manual with Does and doesn’t instruction.

General installation considerations

·        DO NOT run microphone cables near mains, data, telephone or 100V line cables

·        DO NOT exceed 90% of the amplifiers output power when using 100V line (speech only)

·        DO NOT exceed 70% of the amplifiers output power when using 100V line (high level background music only)

·        DO NOT use re-entrant horn loudspeakers for background music unless the loudspeaker has been specifically designed for this purpose

·        AVOID jointing the microphone cable, when this is unavoidable make sure a good screened connector is used, e.g. XLR

·        ALWAYS use a balanced or floating low impedance microphone terminating into a balanced input on long microphone cable runs

·        ENSURE that all loudspeakers are in-phase

·        ENSURE that there are no short circuits on the loudspeaker line before connection ot the amplifier

·        You must NEVER mix 100V line and low impedance speakers on the same system.

 

Separating Fact from Fiction in UL 268

Separating Fact from Fiction in UL 268

What is UL 268, and why are we concerned about changes to this standard? Simply stated, UL 268 Smoke Detectors for Fire Alarm Systems is the Underwriters Laboratories safety standard for smoke detectors connected to fire alarm systems. There is a separate document UL 217 Standard for Smoke Alarms, for stand-alone devices that detect and sound an integral horn and are typically found in residential occupancies. 

So what has changed? First, the materials we have in our homes and offices today. The UL 268 6^th and UL 217 7^th edition testing standards were based on a legacy room that was filled with natural materials such as wood, linen, cotton, and silk. Today’s modern rooms contain more synthetic materials such as polyurethane foam, polyester, nylon, and engineered wood. In a legacy room, a fire can take up to 25 - 30 minutes for flashover to occur. In a modern room, that time is shortened drastically, with flashover occurring in 3 - 4 minutes. With the change in common furnishings and building materials, egress or escape time has gone from 17 minutes in 1970 to 3 minutes today. Due to this decrease in time available for egress, it is necessary to ensure we have early warning while minimizing nuisance events. The new 7^th edition 268 standard will narrow the detector sensitivity range to provide the early warning for notification and occupants.

The second major change to the UL 268 standard was to address nuisance alarms. NFPA 72 2022 edition defines a nuisance alarm as “An unwanted activation of a signaling system or an alarm initiating device in response to a stimulus or condition that is not the result of a potentially hazardous condition.” These changes were made to the existing UL 268 and UL 217 standards based on the results of several studies including the “Smoke Characterization Project” done by UL for the NFPA Fire Protection Research Foundation. This project had the following objectives: Develop smoke test protocols on selected materials in residential settings, develop smoke particle size distribution data and profiles for non-flaming and flaming modes of combustion, and provide data / analysis for potential initiatives. These initiatives included recommendations for The Standard for Smoke Alarms, UL 217, as well as providing data on materials and additives that could impact the advancement of technology for smoke sensing devices and smoke suppression.

The most significant of the changes to UL 268 are the additions of three fire tests: one based on cooking nuisance, and the other two based on polyurethane foam fire tests. Detection technologies for years had been based on either photoelectric or ionization principles. Ionization devices monitor the change in current created when smoke particles impact the ionized air between electrically charged plates. Photoelectric detectors detect the scattering or obscuration of light due to the presence of smoke particles in the detection chamber. It is critical that the engineer of record select the appropriate detector based on the space to be protected. However, these changes to materials in the spaces led to challenges with detection. Newer devices are based on a multi-sensor or multi-criteria to meet the early warning requirements while providing system stability. The new tests that were added utilize polyurethane foam to verify that detectors respond sooner to flaming and smoldering synthetic materials. They are also focused on nuisance alarm resistance to provide detectors that are less sensitive to nuisance events such as burned toast or hamburgers. These tests compress the sensitivity window by 70% from 3.5%/FT to 1.3%/FT.

This shift in sensitivity will challenge single sensor technology devices. Multi-sensor detectors will become the dominant solution as they are able to provide the early warning and minimize nuisance alarms.

In summary, the change from UL 268 6^th edition to 7^th is the biggest change to UL test standards for smoke detectors in the past 25 years. It was necessary due to the changes in materials in our homes and businesses. The new tests are focused on nuisance avoidance and providing a quicker response to smoldering synthetic materials. In today’s built environment, the furnishings and building materials used on a regular basis burn much faster. Occupant egress time has decreased from 17 minutes in 1970 to just 3 minutes. The updated standards will provide notification to occupants in a timely manner while minimizing nuisance events.